The open source clones of Alpha Go are my favorite AI sparring partners. There are several to choose from, and also several Go board applications.

My favorite open source Alpha Go clone is Katago https://github.com/lightvector/KataGo.

There are several different open source Go board/sgf editor applications on which to run Katago; I use several.

KaTrain is my favorite: https://github.com/sanderland/katrain

I also use sabaki: https://github.com/SabakiHQ/Sabaki/releases

and q5Go: https://github.com/bernds/q5Go

for batch review of Go games goreviewpartner is good: https://github.com/pnprog/goreviewpartner

For chess I like nibbler, which uses an open source version of Alpha Zero, Leela Chess Zero: https://github.com/fohristiwhirl/nibbler