I love seeing what you all have! I have a floor layout right now. It's about 10 x 5.6, and I run 4 loops 027, 031 036.
I have an outer O36 loop with a passing outside siding with two o36 switches from the add-on Lionel Fastrack kit. That outside loop has two 10" straights before the switches on the 5.6' curved side. I can run two trains on that.
Next loop is 036 with one 10" straight. I can run one train. Next after that is MTH 031 loop with a one half straight section at the curve to get it into the 036 second loop.
Last is an 027 tubular loop, no straights on curves. I run old postwar on that mostly, and on the MTH loop I run a subway in auto mode, and the 036 2nd loop the same, or perhaps another passenger train. The outer loop with the passing lane always runs two passenger trains.
I run some postwar, but mostly MTH Railking and Lionel LC starter sets.
I could build a table, but I'd have to go down to 4 x 8 or 4 x10. I'm looking into ways to get at least three loops including the passing lane on that. Don't know if I can, maybe with an elevated section. I run almost all passenger trains/Budd Cars/subways. Thank goodness for tight turns.