The best replacement for ssr is scr.

The best alternatives to ssr are rated as following:
★★★★★  scr
★★★★★  emr
★★★★  relay
★★★★  contactor
★★★★  pitster
★★★★  pitster pro
★★★  ford lightning
★★  orion
★★  mechanical relay
★★  triac
★★  trxus
★★  xxr
★  627
★  apollo
★  coolster
★  microsatellite
  enkei
  advan
  trxus mt
  okw
  686
  thumpstar
  tsl radial

Your alternative for ssr is not listed? Suggest!
Speaking about ssr, one probably shouldn't forget about pwm.

Other search terms related to ssr and their ratings are:
★★★★★ pwm
★★★★ inductive load
You have in mind a companion for ssr and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ssr in all years. Click on graph for more.
ssr
scr
emr