With "just" those tools you can do almost anything!
What tool post do you have now on the lathe?
If only a rocker or 4-way type, maybe you need to build an upgrade like a quick-change tool post.
There are a few styles look up Aloris, Norman (easier to make).
If you already have a quick-change, then how about some more tool holders?
User
@mickri made a nice norman-style one here:
https://www.hobby-machinist.com/threads/tool-post-holder.69487/
You could make a carriage stop that clamps to the lathe bed; very useful for repeat parts.
Again there are many types, single finger, multi stop, indicator based ones, etc.
Is there anyway to mount a rear tool-post to your lathe. Those are great for parting.
How about tooling for the mill?
I know I can never find the slitting saw arbour that I need and usually have to stop and make one in the middle of doing something else.
There are several styles of mill vise stops that are useful; some clamp to the jaw edge, some to the table.
Look at the ones from Edge Technologies for ideas, then build your own version.
You could build a tooling plate and clamps for holding stuff too small and awkward for the mill vise.
What ever you decide to build, please take some photos and post the build here.
Have fun and Be safe!
-brino