#20: Barnes Opening (1.f3). Awful. Just awful. Not only does it weaken the king, it's also pointless.
#19: Grob Opening (1.g4). Better than 1.f3 because at least the Grob helps you develop (2.Bg2 is now a possibility), but it still somewhat weakens the king.
#18: Amar Opening (1.Nh3). Numbers 18-13 are all about the same in my opinion. They're all pretty much pointless. Out of all of those, this is probably my least favorite by a slight amount. Why wouldn't you develop the knight towards the center?
#17: Sodium Attack (1.Na3). Again, why not develop it towards the center?
#16: Kadas Opening (1.h4). I will no longer want to possibly castle on the kingside later on in the game. Also, just about useless.
#15: Ware Opening (1.a4). I will no longer want to possibly castle on the queenside later on in the game. Also, just about useless.
#14: Clemenz Opening (1.h3). Great if you want to play black. I don't know why you would want to do that, but okay.
#13: Anderssen Opening (1.a3). Again, great if you like playing black more than you like playing white.
#12: Polish Opening (1.b4). It's just better to control the center. But at least it's not pointless, and it doesn't weaken your king.
#11: Van't Kruijs Opening (1.e3). This will block in your dark-squared bishop. It's not bad, but not the best.
#10: Mieses Opening (1.d3). Pretty much the same for the opening above, but it blocks in the light-squared bishop instead.
#9: Saragossa Opening (1.c3). About a half a year ago I went through a phase of really liking this opening. It actually isn't terrible, but there are moves that are more useful. 1.c3 often transposes into the London or possibly some sort of Trompowsky or Torre but with c3 played early, so you might as well play d4 on move one.
#8: Nimzowitch-Larsen Attack (1.b3). Decent. I don't have much to say about this opening.
#7: King's Fianchetto Opening (1.g3). Not bad, but I prefer 1.Nf3 first.
#6: Bird's Opening (1.f4). This is often talked about as a joke opening, but it is actually a good move, and often quite aggressive. I have a friend with a 2100 FIDE rating who plays the Bird OTB whenever he plays someone he thinks prepared for his regular opening. The one problem it has is that it can weaken the king.
#5: Van Geet Opening (1.Nc3). I play this in blitz games every once in a while and I have decent success with it. I prefer 1.d4 or 1.e4 in rapid games, though, because I want to keep c4 as a possibility later on.
#4: English Opening (1.c4). Solid. There's really no problems with it, I just like the other three moves I haven't named more.
#3: Reti Opening (1.Nf3). A great opening. This leaves you with many possibilities for move two: 2.g3, 2.c4, 2.d4, 2.e4 if black doesn't play 1...Nf6 or 1...d5, 1.b3, etc. This is my dad's favorite opening for white.
#2: Queen's Pawn Opening (1.d4). Barely losing to 1.e4. I played 1.d4 for years (Accelerated London mainly, with Queen's Gambit every once in a while) before I ever tried 1.e4, and I loved playing it. It follows the simple opening principles and has many decent openings it can go into.
#1: King's Pawn Opening (1.e4). Really this is just due to personal preference. I think 1.e4 and 1.d4 are equally good. They both follow all the simple opening principles and are both great. But 1.e4 has my favorite opening: the Italian. The Italian is the main reason I like 1.e4 most.
#12 Van Geet Opening (Nc3)
The van geet opening is in my opinion very underrated. First of all, it's one of the best transposition chess openings, as it can lead to the closed sicilian (If black plays c5), Vienna game (If black plays e5), either the falkbeer variation of the vienna or the scandinavian variation of the alekhine's defense (If black plays nf6) Or either the richter veresov attack or the rapport jobava system (If black plays D5)
But even if you don't want to transpose to other openings, you can play the main line of the van geet opening which is 1. nc3 d5 2. e4. Usually the opponent plays 2. d4 and you play 3. Nce2. It will lead to a closed game very often where your plan is to put the Knight on G3, develop the light squared bishop to c4 (Although in some positions developing the bishop to b5 is better), then close the position with d3 and then either playing nf3, or if you want to get aggressive push the F pawn to F4 (stockfish doesn't like the second plan though, but it's interesting). It works very well and i think this opening should be played more often.