Let's get quantitative about this. There are UUs in seven of the game's eight eras, so we can call Industrial, Modern, and Atomic "late" for units.
Late-game European UUs, counting America as European: B-17, Panzer, Norwegian Ski Infantry, Hussar, Cossack, Carolean (six in total, two horse units)
Late-game non-European UUs, counting Brazil as non-European: Zero, Pracinha, Mehal Sefari, Comanche Riders, Berber Cavalry (five in total, two horse units)
There are UBs and UIs in only four of the game's eras, so let's call Medieval and Renaissance "late" for buildings/improvements.
Late-game European UBs/UIs: Ceilidh Hall, Coffee House, Feitoria, Polder, Chateau (five in total)
Late-game non-European UBs/UIs, counting Brazil as non-European: Brazilwood Camp, Satrap's Court, Candi, Longhouse, Kasbah, Mughal Fort, Wat (seven in total)