Comment by bbanyc
1 day ago
US Patent #5,662,332 - Trading card game method of play, inventor Richard Garfield, assigned to Wizards of the Coast https://patents.google.com/patent/US5662332A/en
Obviously there have been lots of other TCGs, but up until that patent expired in 2014, they had to either be sufficiently different from MtG to avoid the patent, or pay royalties to WOTC.
There were also cases that just invalidated it in place. It was a dead patent. You still can't call turning cards to indicate use "tapping" though.
edit: to be clear, anyone can copy every single element of any board game, as long as they don't infringe on the game's copyrights or trademarks i.e. the art and the text, including the names of things. This is absolutely true in the US, but not necessarily true in other countries, and I'm pretty sure false in Germany. Also, there is a European alliance of board game designers who will blacklist retailers that sell your copied game, and the sites that promote it.
Monopoly harassed the game "Anti-Monopoly" forever over this, but eventually when the law became clear, realized they would lose, so settled by paying the designer and giving him a perpetual license to any IP involved in the mechanics of Monopoly so there wouldn't actually be a court decision recorded that officially invalidated their patents (I'm not sure if it was still Parker Brothers by the conclusion.) They could theoretically go after people still, and probably have sent letters (everybody who was going to get rich off the next big board game in the 60s and 70s made a Monopoly clone.) But after the Anti-Monopoly guy published about the experience, everybody knows that any threats are toothless.