These are the tokens created especially for the Use-a-Thons, one for the main prizewinners and an "Honourable Mention" for outstanding contributions as determined by the organizers. Token details can be found at https://wiki.byteball.org/Use-a-thon#Use-a-Thon_Tokens.
Steem entrant details, including links to their competition blog posts, are at https://wiki.byteball.org/Use-a-thon/steem#Known_participants.