Cactus Chat is probably the easiest. Just download the app and it has a few built-in model options. The best of those is probably Gemma-3 1B Q4 but on my Pixel

Cactus Chat is probably the easiest. Just download the app and it has a few built-in model options. The best of those is probably Gemma-3 1B Q4 but on my Pixel 10 Pro I find the best performing model it can reasonably run is Qwen3 8B Q4_K_M. You can download and run any GGUF compatible model with that app.