(from "Superbombovozi Stalina")
In early 1930th projected more monstruosly bombers, than TB-6/ANT-26 and ANT-28.
TB-7 project (not Pe-8 - it's other project) - span ~200 metres (~650 foot), 8x2000hp engines, 30 t bombs on range 1200 km or 15 t on range 2400 km, and full weight to 150 ton.
STB (SverhTyazholy Bombardirovshik - Superheavy bomber) - bigger than TB-7, 25 t bombs on range 2500 km, I haven't data about span, but, bigger than TB-7.
Are there any sketches of the 656-foot span bomber or the STB? I could barely fathom the notion of a Soviet design for a 600+ foot span heavy bomber, but it's known that the USSR didn't build large strategic bombers in huge numbers given its emphasis on tactical aviation in WW2.
In early 1930th in USSR created programm "about air fleet". By this programm, needed builted huge fleet, for destroying navy, bases, plants. TB-4, TB-4MG, TB-6, TB-7, STB - special bombers, TB-8 and TB-9 - universal, for paratroopers. Based on TB-3 created a "cruisers", for escort of heavy bomber, and, TB-3 reclassifited from heavy bomber to medium bomber. This programm was very heavy and difficult for USSR, and projects TB-7, TB-8, TB-9, STB was closed. But, in "small" version of programm, implied a huge air fleet, 96 TB-6, 196 TB-4 and more TB-3, to 1937-1939. But, to 1935 this programm was closed.
Also, for TB-3 created assault weapons - "We need a heavy assault airplane". Constructed TB-3 with 76.2 mm front guns, in three version - 3 x M1927 short-barrel guns, 2 x M1927 and 1 x M1931 high-velocity AA gun, 3 x M1931. Also, created heavy ROFS-203 rockets, "super-Il-2"

In early 1930th analogical huge programms created for navy - giant gibrid cruiser-carriers, superbattleships (16x18", 9x20", 6x21" guns), underwater cruisers in 5000+ tons - and for land forces - many types of tanks, from 15 to 600 tons, self-propelled 180, 203, 305, 406 mm cannons, 305, 400, 500 mm hovitzers.
USSR "perebolel" (got sick) of megalomania in 1930th, and in WW2 produced most effective machines for total war. Stalin wasn't a Soviet Hitler