Routers on Ethereum

I always hear the term “Router” and sometimes see it on etherscan.

One big one is Uniswap Router, im guessing V2 & V3 are different routers?

Can anyone give a list of all routers on the ethereum blockchain? Well all the ones that are still around and relevant today,

And also a dex aggregator like paraswap/1inch/metamask use other routers?

Like how can i find which dexes have their own router or if they use an established router like uniswap v2.