Concept art for Sci-Fi video games is often great for ideas because you can see all the scrapped ones too and how the character designers evolved and picked out their favourites. Also see if you can find the influences when looking at character designs.
For example, Mass Effect was heavily influenced by 80s Sci-Fi movies:
But when the series got more mainstream, a lot of the designs got more blocky and influenced by more modern sci-fi games and movies:
So you can see this move from these rounded organic shapes and bright colours on a plasticky finish to these more metallic edges and chunky angles with a slight bevel that feel more modern and influenced by Japanese mecha and current military tech.
Other Sci-fi and Science-Fantasy games I like for design like this are:
Overwatch, because the game wanted to be bold, colourful, exaggerated and all about making the characters cool heroes you want to play with big personalities and a variety of cultures:
and Star Ocean 4, which... I never actually got around to playing actually but I've always thought the designs were really cool at achieving a very clear goal: VERY recognisable JRPG Fantasy character archetypes but with a Sci-Fi look. The shapes and silhouettes and even colours immediately tell you like "this is the young heroic knight errant guy", "this is the cute archer heroine".
You can see how the basic designs are inspired most by Fantasy, but then the chunky shapes and use of cut-ins with that half-hexagon shape and things give a sci-fi feel. Overwatch has a similar approach like "this guy is a medieval knight" "This guy is a cowboy", "This lady is a fighter pilot", "This robot is a Buddhist monk". Sci-Fi and Fantasy designs are often more based on history, current and past culture and present fashion trends to build on the audience's existing cultural knowledge, so you'll often see a character who is serious and neat wear an outfit where the shape evokes a sharply cut modern business suit, but they just add some sci-fi flourishes like instead of buttons it fastens differently, and the shapes have cut-outs and maybe it has some pointy shoulderpads. The audience will recognise that "this is sci-fi but it's a serious businessperson with money".