I couldn't give a suggestion without knowing what you've already played. That said, Titanfall 2 was the game I most recently got 1000gs on. Fairly easily achievable within ~20 hours. Maybe less if you're better at the gauntlet than I am. It took me like 3-4 hours out of the 20 just trying to beat the gauntlet time. I also didn't play it on master difficulty from the get go, so really I think this might be a possible 1000gs in ~12 hours. Another fairly easy 1000gs is Child of Light. It's a little old, but it's a beefy good game, and pretty cheap. You could probably do this one in 8-10 hours.