There will be fewer chances for champions listed in the monster category to get new skin.
Last year, Riot Games admitted that they’re no longer going to make lower-priced skin. Since these skins don’t have any special effects along with the fact that very few people are willing to buy them. Also, it takes too much time to design them. Riot Games expressed that “monster” champion skins “don’t sell very well,” which results in them trying to make as few skins for these champions as possible.
Therefore, champions that are list as monsters like Rek’Sai, Skarner, Cho’Gath, Urgot, Rammus,… will have to wait for an extremely long period of time to get a new skin, usually from hundreds to one thousand days.
While Riot has “clarified” there aren’t many players who are interested in these champions or any appealing lore with good ideas for their skin concepts. However, at last, the community has pointed out that their skins don’t sell as much as Ezreal, Lux, or Ahri skins. Many players state that this is one of the main issues of Riot and agreed that monster champions in League of Legends are special creatures with high potential to create skins with special skill effects from their abilities.
Finally, if Riot Games want to sell skins of monster champions, they should find a way rather than find a justification. If not, players would find it hard to spend money on buying any of their potential champion skins.