Theres several open source options you can use.

The highest github stars one is called `zed` another one i've heard about is `Cline`

theirs also a few that yc backed ones:

`Void`

`Continue`

`PearAI`

For what its worth the non yc ones have way more github stars but im sure the yc ones are good too. I think `Continue` is the biggest yc one.