Board games translate to a browser tab better than almost any other genre — no physical pieces to lose, no need to find three other people in the room, and the AI opponent is always up for another round. These three cover the range from serious to casual.
Neon Four — a minimax engine, not a scripted bot
Neon Four is the connect-four style drop game, and its opponent searches ten moves ahead with alpha-beta pruning — timed on the worst case, the opening board, so it never stalls. It isn't a simplified move-picker that just blocks your last threat; it will set up a double threat you can't answer. Good for anyone who wants a genuine test, not just a casual time-killer. There's a hot-seat two-player mode as well.
Checkers — mandatory captures, real multi-jump chains
Checkers plays by the full standard rules: captures are mandatory whenever one is available, multi-jump chains have to be played out in full, and reaching the back row kings a piece for backward moves. The AI opponent plans several moves ahead, so a careless capture can walk straight into a bigger one waiting behind it.
Ludo Dash — classic Ludo, rebuilt as a real 3D board
Ludo Dash takes the dice-and-pawns game most people already know and renders it as an actual 3D table — wooden board, rolling dice, molded pawns — instead of a flat top-down grid. Roll a 6 to leave the yard, then race all 4 pawns home before the 3 CPU rivals beat you to it. The lightest, most luck-driven pick of the three, and a good one to have running in the background of a slower afternoon.
All three (and the rest of the catalog) are on the Strategy category page, or browse everything on the homepage.