You can pass --exclude path_or_pattern to restic commands to exclude matching paths in the source directory from the backup.
For scheduled backups (or just as a general practice), you can create "ignore files" that you can pass like restic src/ --exclude-file ~/.restic/ignores/ignore_filename. You can also pass multiple --exclude-filename ... and --exclude ... flags.
You can split your ignore files, i.e. by programming language or purpose. Below are some purpose-specific Restic ignore files.