Variants Puzzles and others: https://chessvariants.training/
https://altcodeunicode.com/alt-codes-math-symbols-italic-letters/
FoW: https://www.chess.com/blog/Illingworth/fog-of-war-chess-grandmaster-strategy
some crazyhouse study for future reference: https://lichess.org/study/OHSQPWgG
Klubai
4 Player Chess
51 011 Nariai (-ių)
Fog of War
5 770 Nariai (-ių)
Variants
4 523 Nariai (-ių)
8 Player Chess
921 Nariai (-ių)
4PC Teams
386 Nariai (-ių)