From the source
Closed models include nearly everything from OpenAI (despite the name!) with open weights models being released from other labs. Famously the Llama series of models were open weights, but more recently the Chinese labs such as MiniMax, Z.ai, DeepSeek and Qwen (Alibaba) have been the leading open weights models, with Google's Gemma series and OpenAI's gpt-oss models generally coming somewhere behind the Chinese ones. Open weights models allow anyone to run the model on their own hardware. Typically models that were worth running required very beefy hardware - but this is rapidly changing, with smaller models becoming far more useful.