Variants!!!!

If you have not played variants in chess.com yet you definitely should. My personal recommendations are:

Chaturanga: Interesting to say the least.....

Fog of war: Stay away from this game mode. For hardcore players only

Blindfold: Fog of war on steroids

Capture everything: Useless feature

Automate: Too easy

Sideways Pawns: Good mode, pretty fun. Doubled pawns aren't a problem anymore

Torpedo: Good mode. Not much to say

Horde: Super fun! One of the unique ones

No castling: Sucks. Just play normal chess. Castling is a great feature, taking it away is just making the game more boring

Note: There are my personal opinions and suggestions. Please do not feel offended if I hate your favorite game mode.