Share your opening repertoire and explain why you choose those openings!

My repertoire:

White:

KIA (e6)
Sicilian: Rossolimo
Ruy Lopez

Caro Kann: exchange variation

Black:
Sicilian Defense (O'kelly Variation)
Nimzo/Bogo Indian Defense

You said in the title to explain why you chose them, yet you didn't explain your choices.

My repertoire

White :

Queens gambit 

Catalan

Tromp

Black

Najdorf against e4 

Grunfeld against d4

Queens gambit decline against c4 and nf3

I prefer d4 openings and opening which are considered good at elite level as I also wants to be elite players therefore I am learnings openings which can help me all through my life I am 16 at this date

I forgot to add it.

I play Rossolimo as I like the idea of doubling the c pawns and either playing c3d4 or h3e5 with later d3c4 restricting black's light square bishop. I really enjoy creating a position in which my opponent has no idea how to continue doing things or force some sort of aggression. As Sicilian players want to be aggressive so I play the most solid line to torture them. And people just don't know how to play against Rossolimo, in fact, you just can't refute Rossolimo setup.

I actually switch to the Italian game against 1...e5, but there is no big difference as I also play d3 in the Ruy, I feel like this is the game plan of d3 Ruy and Itailian game is the simplest and most powerful way to play against ...e5 so I play it. 

I choose KIA because I simply need an opening against e6 Sicilian and the french defense and KIA is a simple, easy and decent option.

I play Sicilian as I think it's the easiest way to equalize against 1.e4 and I used to play the caro and just get tortured by those boring drawish lines. And one good thing about playing the Sicilian at my level is that people always play Bc4 or c3 so you basically need to know how to crush these two dubious lines and you will win a lot. if they go for the open Sicilian the Okelly variation just gives black advantage immediately. Besides, the Sicilian often turns into some interesting position and it's really fun to play.

I would suggest you to play najdorf against open sicilian

And yes at lower lvl 3 . Bc4 and 2 c3 Or 3 

C3 are very common and you are gonna get it 7 out of 10 times which signifcantly decreases our job as sicilian player

And at elite lvl you r gonna get the open sicilian or closed sicilan 8 put of 10 time so this is your main focus at elite lvl

Hey I just had a doubt what you play against sicilian if black goes e4 c5 nf3 d6 

Bb5

As White:

Italian Game/Fried Liver Attack (offers great attacking chances, gives White a comfortable advantage). 

As Black: 

1. e4 Scandinavian Defense (easy-to-play, solid, but good chances).

1. d4 Dutch Defense (variety of systems to choose from, Classical Dutch, Stonewall Dutch, Leningrad Dutch. Decent chances with a kingside attack and good central presence).

I am just curious what do you play when 2…dxe4, do you gambit your f pawn or what?

WHITE: Catalan

BLACK: Caro-Kann / Semi-Slav

I have tried many openings while trying to decide my repertoire, but these are the ones I chose and I feel like they fit my style and I like to play the positions that arise from them. I also like the Ruy Lopez, but there's just too many variations and so many options after 1. e4 for Black to avoid the Ruy Lopez so I switched to 1. d4.

Of course there are other openings as well which I need to know when I play those openings, but I only listed my main options.

White - 

Scotch Gambit, because why not.

London System, because it's fluid, can be played against anything, and the plans are easy to follow.

Trying to integrate the Vienna, since it's a rarer but solid opening.

Black - 

Alekhine's Defense, because I'm a masochist.

Englund Gambit, because there is a 1 in 1000 chance to mate on move seven.

Benoni/Old Benoni, because it throws people off. That's literally the sole reason. 

I believe in the philosophy that chaos on the chessboard favor the side with the disadvantage. This is why I play much more conservative as white than black. Black need to take serious risks in order to get winning chances, and he can often do so by creating a chaotic position.

The provocative playstyle is what fit my playstyle the best. But how does the white side play provocatively? Well, that question I have been trying to answer with no real success. Black can always deny the center and play kingside fianchetto. This is why I have a MUCH more solid repertoire as white than black. My white side is filled with ideas rather than lines, while I can say the opposite to my black side.

Black:

- Against e4: Alekhine

I have a very provocative playstyle that fit this opening very well. I do not have a clear preference for tactical or positional games, but I do like heavy unbalanced positions since I can get bored with symmetry. 

- Against d4: Chigorin

Again, this fit the provocative playstyle very well. But the chigorin is more unknown that the alekhine, my favourite opening by far and in official FIDE games, this opening has scored 100%  for me out of 15ish games.

White: 

Main system: 1.e4

- against e5:

I play the ruy lopez exchange variation since the ideas are easy to remember and its very hard to mess up. White is playing for the endgame, and if one is reached he will most likely manage to win it since black's pawn structure cannot create a passed pawn. 

- against sicilian:

My system is based around the maroczy bind: Prins variation against dragon, Nb5 + c4 against Taimanov.

Since black can avoid the maroczy by playing  2...Nc6 and 3...Nf6 I play the rossolimo against 2...Nc6.

- against caro kann:

I play the accelerated panov attack since I want to avoid the endgame variation which in my opinion looks better for black. My idea is to delay d4 for as long as possible.

- against french:

Against steinitz I go for burn variation while I play a weird sideline against the winawer with Bd2 followed by Nb5.

I also have a side system based around Richter-Veresov attack.

white: reti

black: alekhine/nimzowtisch (e4), czech benoni (d4)

reason:

low upkeep, less tactical, grindy, just play chess

d5

Against 2.Nf3 I usually play …Nf6 (I am aware it’s not as good)

White:

Reti Gambit/Queen's Gambit, both are solid systems that offer white good chances.

Black:

e4: Nimzowitsch defense, rare, but quite strong defense.

d4: Queen's indian or old benoni

White
Vienna Game
A rather unpopular but perfectly playable opening. It also has my favorite trap:

Black against 1. e4
French Defense

While it does sacrifice space and makes your LS bishop bad, oftentimes my opening mission is the same: Target and put pressure on white's d pawn.

Black against 1. d4
I just respond with d5 and play natural opening moves. Specifically will play the QGD when faced with the QG and c5 against the London depending on the move order. 

As White:

1.d4 and then 3 different reps:

A) The Richter-Veresov Attack - My main weapon for the past couple years. I played the BDG almost exclusively for a stretch but being down a pawn OTB every game was too stressful. The Veresov was a logical one to learn since both openings lead to the same range of e4 and d4 positions if they are "declined" - Benonis, Dutch, French, Caro, Pirc etc -- so half of what I knew carried over.

B) The Trompowsky against 1...Nf6 or the London against 1...d5 - I've dabbled with the Tromp off and on over the years but finally put some real effort into learning it better in the past year, to have an opening that bridges the gap between the ecosystem I know and more mainstream chess.

C) The Blackmar-Diemer Gambit - My favorite White gambit. I still play it in blitz, or if all my other openings fail against someone.

D) An as-yet unnamed d4 sideline I discovered and developed the theory for. This is my ultimate surprise weapon and I'm fairly tight-lipped about it.

For Black -

e4 -

A) Nf6 Scandi intending either Portuguese or Pytel (Qd6) - I still play the Portuguese OTB and don't really fear the "correspondence refutation". I looked at other openings over the years before giving up and deciding I hated everything against e4, so I was just going to have to be the "Scandi-master" and I intend to learn and master all the Scandis. Qd8 and Qa5 are on the bucket list. Nxd5 was my original opening and I've mostly shelved it.

B) French Rubinstein/Guimard - A lightweight French sideline rep that I'm working on as a non-scandi answer. Eventually plan to expand into more mainline territory possibly.

Against d4:

A) The Tarrasch Defense, typically the Advance variation (9...c4). I may try to learn the Dubov some time but everyone seems to be playing a Catalan move order these days to avoid it so there doesn't seem to be much utility in doing so.

B) Working on an Albin vs 2.c4 and Chigorin vs 2.Nf3 alternate rep. Originally I played the Von-Hennig Schara but there are moveorders that bypass it while still subjecting you to every critical Tarrasch line after so it's more like a 'supplement' than an alternate rep, which became a bit of a problem.