Throughout Season 4, The Thinker has targeted a dozen metahumans whose powers sprouted when Barry escaped the Speed Force, and it’s been made abundantly clear The Thinker orchestrated it all for very specific outcomes, thanks to his powers of projecting such specific outcomes.
It all made fine enough Arrow-verse sense for him to want metas with relevant abilities like Ralph’s, Brainstorm’s, and Melting Pot’s.
Could six or seven metas not have been enough for DeVoe?
Considering Ralph Dibney’s arrival in Season 4 made a continuity error out of Ralph’s Season 1 namecheck as a victim of the first particle accelerator explosion, I’m wary a comprehensive answer may not arrive.