llama.cpp

This appears to be the backend library of Ollama.

They have a CLI front-end named llama-cli.

askubuntu.com/questions/1461564/install-llama-cpp-locally has some tutorials for Ubuntu. There was no nicely pre-packaged one for Ubuntu 25.04, but build worked on 79e0b68c178656bb0632cb8602d2940b755077f8 In particular it exposed Vulkan support before Ollama did: github.com/ollama/ollama/pull/5059 and it did seem to work, using up my AMD GPU.