I wanted my GIF to be as international as possible, so I didn't add any text to them. Then, as anime GIFs with no text just required capturing and adapting them to the format required in the contest's rules, I rewatched all the latest popular anime series, captured the parts I needed and used FFmpeg comand line program to edit and compress them. I used H.265 codec, trying to make them as lightweight as possible without losing quality, and playing with their bitrate values to achieve that goal. I made them most of all less than 200 kb, but after uploading them to the bot, the size increased inevitably. Despite that, I'm quite happy with the results, although some files got close to the maximum size limit.
EDIT: Also, I indeed used some scenes that I also presented in the first round, but I improved their quality by encoding them with h.265 and made them more lightweight (or tried to at least). If using GIFs from the first round is not OK, it would be OK for me not to get a prize for them.