There's one for sure: The Bobby Fischer one
How many secret achievments in chess.com you know?

The cow. If you upload a picture with a cow and the algorithm recognizes it, you'll get the "Holy Cow" achievement.
Show us your Holy Cow achievement first

Juggler : 20 Daily Games at Once
Chess Marathon : Play a Game with over 100 Moves
Full House : Win without losing any pieces

man vs machine
That's not secret, just no longer possible since there aren't bots in Live anymore.

man vs machine
That's not secret, just no longer possible since there aren't bots in Live anymore.
If it is possible to obtain it if you contact the support, I have obtained it that way.

why would you contact support just to get a trophy lol
Bored senseless, I imagine.
How many secret achievments and them complete way you know? I cant find reply for my question! Sorry for my english(