Some things yes, some things no. For a while it was illegal to implement a loading screen mini-game for anyone not published by Namco. Now the patent has expired so everyone is free to do so.
Most game mechanics aren’t patented and are used so widely they would be impossible to patent. Only very specific game mechanics get patented and protected, but the only way to know which ones and whether or not you may violate that patent and what you can do to be different enough not to violate it is to talk to a patent lawyer. If you don’t, you could be sued, though these types of patent suits are generally not served at the indie developer, they’re generally exercised on companies that can actually pay remuneration. This is NOT LEGAL ADVICE, just a general observation.
This article is about ten years old now so some of these patents have probably already expired, but it should give you an idea of the kind of specificity that may actually be granted a patent when it comes to video game mechanics: Patented Game Mechanics That Might Surprise You - GameSpot
Runtime DataTable : Import and export game data to and from CSV or Google Sheets while your game is running!
GSheets Operator : Interface with Google Sheets, add new and delete old sheets, edit columns and rows, make in-game spreadsheets and more!
easyCSV : Read data from any CSV and put them in an easy-to-access string map!
iTween : Free, smooth, procedural object animation