Unity SDK
The unity game engine is known for its beginner friendly approach and cross platform support including WebGL, ios and android. Build once export everywhere. The Solana Unity SDK comes with NFT support, transactions, RPC functions, Phantom Deep lLinks, WebGL connector, WebSocket connection support, mobile wallet-adapter and anchor client code generation.
Docs
Verified Unity Asset Store Listing
Example Games
Unreal SDK
Unreal engine is known for its great visuals and node based scripting framework. The Solana sdk was originally build by the team of Star Atlas.
Flutter
Flutter is an open source framework by Google for building beautiful, natively compiled, multi-platform applications from a single codebase.
Next.js/React + Anchor
One of the easiest way to build on Solana is using the Web3js Javascript framework in combination with the Solana Anchor frameworks. For more complex games I would recommend using a GameEngine like Unity or Unreal though. The fastest way to set it up is:
npx create-solana-dapp your-app
This will generate a great starting application with wallet-adapter support. A benefit of using Next.js is that you can use the same code in the backend and in the frontend, speeding up development.
Python
Python is an easy to learn programming language which is often used in AI programming. There is a framework called Seahorse which lets you build smart contracts in Python.
Anchor Playground Example
Source and Docs
Native C#
The original port of Web3js to C#. It comes with a bunch of functionality like transactions, RPC functions and anchor client code generation.