Alternatives to ChessKid
The safest place for kids to learn chess. If that's not for you - or you want to try something different - here are apps that overlap on features and use cases.
ChessKid alternatives get searched for one of two reasons: a kid outgrew the gamified UX (typically around age 12), or a parent wants a single subscription that covers both their own play and the kid's. Both are reasonable; the answers are different.
First-line alternative
For an outgrowing kid, Chess.com (the adult version) under a Family Plan is the natural step. Same Chess.com Diamond features, $49 a year for up to 6 accounts, and the older kid can opt into the wider community at a parent-controlled pace. For most 12-14 year olds who started on ChessKid, this is the right migration.
Second option
For a kid who needs a less commercial environment, Lichess works with parental supervision. Chat and friend requests can be disabled; the learning content (lessons, studies, puzzles) is free; and there's no upsell pressure. The trade-off is that Lichess wasn't built for kids - there's no kid-friendly UI layer, just toggleable safety settings.
Verdict
Most parents who reach this question already know which side fits. If the kid plays in a club and is starting to enter tournaments, the Family Plan plus Chess.com path is more useful. If the kid just plays for fun and the parent values an ads-free, no-upsell environment, Lichess with chat disabled is the right answer.

SparkChess
Media Division SRL
Friendly casual chess with quirky AI characters.

Chess.com
Chess.com, LLC
The default home of online chess.

Lichess
Lichess (charity)
Free, open-source chess. Forever.

Chess King Learn
Chess King (CHESSQUEEN INC, ex-Convekta)
Huge Convekta course catalog in one app.

Dr. Wolf
Chess.com, LLC
An AI that plays with you and explains every move.

Magnus Trainer
Chess.com (formerly Play Magnus)
Gamified learning with lessons featuring Magnus Carlsen.

Square Off
Infivention Inc. (Square Off / Emotix)
Robotic auto-move chessboard with online integration.

Chessable
Chessable (Chess.com)
MoveTrainer + spaced repetition for openings and tactics.