LMSYS’ Chatbot Arena (
https://huggingface.co/spaces/lmsys/chatbot-arena-leaderboar...) is widely regarded as one of, if not, the most reliable open benchmarks for LLMs. Real users provide prompts to chatbots and then blindly pick the best response. The only drawback is that the leaderboard is restricted to the most popular models and, even then, it can take a while for new models to be added. This is understandable given the considerable ongoing costs associated with continuously updating the leaderboard.
There is also the Open LLM Leaderboard by HuggingFace (https://huggingface.co/spaces/HuggingFaceH4/open_llm_leaderb...) which aggregates a number of benchmarks, some (eg, MMLU) more trustworthy than others (eg, TruthfulQA). There are real concerns, however, that ML practitioners are gaming the leaderboard by contaminating their training data with evaluation data.
There are a number of other leaderboards such as OpenCompass (https://rank.opencompass.org.cn/leaderboard-llm-v2) and Yet Another LLM Leaderboard (https://huggingface.co/spaces/mlabonne/Yet_Another_LLM_Leade...) that I have seen suggested although I personally have found the most success with Chatbot Arena and the Open LLM Leaderboard.
I would also suggest checking out the LLM Explorer (https://llm.extractum.io/), which has all of these benchmarks and more in single location and allows you to sort and filter by a wide range of variables. That has been particularly helpful for me when trying to find models that will fit on my GPUs.
N.B. I am not affiliated with any of the benchmarks and services mentioned above.