Websites like Fansub.ru or Kage.project often host .ass or .srt files created by various translation groups. These are ideal if you already have the video files and want to toggle the subtitles.
Look for releases tagged by these groups, known for their work on slice-of-life titles: Convenience Store Boy Friends subtitles Russian...
Frequently handles subtitles for seasonal romances. Websites like Fansub