Apple Watch Sport, Series 0, 42 mm - Gold
Apple Watch Sport, Series 2, 42 mm - Gold
Apple Watch Sport, Series 4 + Cellular, 44 mm - Space Gray
Apple Watch Stainless Steel, Series 6 + Cellular, 44 mm - Graphite
No point in jumping the Series 7 with its minor updates for me, will wait and see what Series 8 has to offer.