Kikaida on Sidemachine
and Kamen Rider 1 on New Cyclone
Henshin Ninja Arashi
and Kamen Rider 1
(would require time travel as Arashi was in distant past)
Robot Detective K, Kamen Rider V3, Kikaida-01
these three series were all from 1973,
probably filming on same lot at same time
Kamen Rider V3 assisting Spider Man
Miyauchi, Hiroshi did appear in Spider-Man
but not as Kazami, Shiro/Kamen Rider V3
Kamen Rider Black never worked with the previous Kamen Riders.
He's the first Kamen Rider not to have met his predecessors.
Kamen Rider Black RX did meet those who came before.