It Would be nice to see some retro color filters like lomo, holiday, bloom, etc.
in shotcut, something like instagram filters for video.
You can use LUTs. (Filters>LUT (3D)
Google for free LUTs. (.cube and .3dl)
Try using the Color Grading, Old Film: Technocolor, Sepia, and Saturation filters. Some of these let you save as a preset.