Now that a lot of SETI users have migrated to other projects, I can see a low task queue for Nvidia GPU users.

Most projects are out of work, except the CPU based ones.

Any idea if there's perhaps some sort of trigger (eg: like schools start), that will trigger more work?

I believe a lot of people (especially Americans) pause high-powered computers when the hot summer weather arrives - they don't see the point of heating their houses up, and then paying for air conditioning to cool them down again.

GPUGrid is a great project for Nvidia. In fact, it is CUDA only.
It is worthwhile work, and they (for once) have plenty of work units.
The new app is working well on both Linux and Windows, if you have a recent card and drivers.

I'm already running GPU Grid, prime grid, and the Collatz (which are running out of work for Nvidia GPUs).

I just added numberfields, Einstein and SETI, though I don't prefer those projects. (For one, I don't believe in aliens, and two, numberfields isn't running well on RTX GPUs. They use only 140W out of the allocated 200W, and doubling them up, they run at 155W, and Einstein isn't any better).