No Man’s Land is a solitaire card game that’s supposed to simulate being a sniper in the Great War.
Roundwood’s World has an excellent photo illustrated post on how he built a trenches terrain board. It’s something I’ve always wanted to do.
Here’s a set of rules for Memoir ’14, a World War Variant of Memoir ’44. I rather think the great war would work better with this rules set than WWII.