I managed to identify most of the figures mentioned in the last post. As suspected, most are Star Trek Citadel figures from the 70s, and a few Galactic Grenadiers from Ral Partha, also from the 70s.
All figure codes (ST for Star Trek, GG for Galactic Grenadiers) are shown in the image above.
One figure remains unidentified (bottom row), but he could as well be a modern soldier, not a science fiction figure.
Update: identified as Citadel Spacefarers S4 figure (see comments).