play nimzo indian or KID
Help for smooth openings

I recommend Nimzo and Bogo since they're [imo] the most simple, flexible and solid ones. King's indian and Queen's indian are sharper, same for Grünfeld. I can send you some resources about Nimzo if you're interested, it was my main for a whole year.
you could also play grunfeld opening against declined queen gambit
grunfeld has too many variations and too complex. I don't want to learn it.
I recommend Nimzo and Bogo since they're [imo] the most simple, flexible and solid ones. King's indian and Queen's indian are sharper, same for Grünfeld. I can send you some resources about Nimzo if you're interested, it was my main for a whole year.
yes,thanks!

dutch is a more aggresive approach & I play it because even if you lose it will lead to attacking games which I find fun, but the dutch is objectively bad. The KID or the nimsowitch are solid openings which will let you equalize with white

Against the london I use the anti london, you gambit the c pawn to disrupt their structure and gain quick development. I like the slav more than the normal defense in the queen's gambit declined.

Hi RainFestival,
The Benko Gambit or Nimzo-Indian Defence are extremely fun openings to always play for the full point and put lots of pressure against white.
For the London, you can play a quick c5 and Qb6 (I have won many games like this) - e.g. 1. d4 Nf6 2. Bf4 c5 3. c3 Qb6 - London players are quite bad against this, and if they push (1. d4 Nf6 2. Bf4 c5 3. d5), then you can play b5 immediately and go for lots of play on the queenside, and fianchetto your dark-squared bishop (play it a bit like a Benko but without sacrificing a pawn) - the pressure on the queenside often leads to winning some pawns, and sometimes, some nice tactics appear.
Another way to play against the London (which I am now learning) is to play with c5, b6 structures and fianchetto the light squared bishop. These are extremely dynamic structures that usually arise in the Nimzo-Indian Defence, and if you get some experience with the c5, b6 (and often d6) structures, you will be destroying clueless London System players. An example of getting these structures in a game might look light - 1. d4 Nf6 2. Bf4 e6 3. e3 c5 4. c3 b6 (you can also play 4. Qb6 here if you like that system against the London).
Hope this helps

Against the London and other noncritical openings, you can usually just copycat them. If they're not gonna go for an immediate advantage as white, you might as well, in the words of Dr. Siegbert Tarrasch, "answer stupidity with stupidity."
Against the QGD, I don't know how you'd get anything other than a smooth game. It's not known to be the most wild or tactical variation, so just developing naturally will get you a nice and boring game.
May someone recommend me some smooth defense against London System and Queen's Gambit Declined, thx