The temptation is to refer to these as Traveller miniatures but some are part of the Laserburn range which had its own unique set of rules. The figures shown are by a variety of companies including Citadel, Laserburn, Martian Metals, and Asgard. There may be others tucked in there but I am not really sure. The figures are over 30 years old give or take a year. These are my only award winning figures having taking first place for SF/Fantasy group at some in the distant past Origins convention. Most of the painting was done with enamels.
15mm had seemed an odd scale for an RPG. RPGs usually relied on larger 25mm and 28mm figures. It did make Traveller unique for its time and facilitated the introduction of the Striker rules for mass combat replacing the earlier simplistic rules found in the original RPG. There were also rules like Snapshot and a later more streamlined version of the Snapshot rules in the Azhanti High Lightning game set that allowed battles using individual figures rather than using multiple based figures. With the Snapshot type rules, figures could use maps of spaceships, outdoor areas, and buildings as handy battlefields. Eventually, Traveller began using 25mm figures with several companies licensed to manufacture them. Licensing really would seem unimportant as any figure could function in a Traveller game but the alien races were pretty unique.
All the figures are nice though I prefer the Laserburn and Citadel (now RAFM) figures. Vehicles have never quite kept up with the range of figures. There are more manufacturers offering vehicles these days but all seem grounded in 20th century technology.