For example: Nidalee mid/top. Kha’Zix mid. Sejuani top or support. Amumu top or support. Zac top. Graves ADC. Xin Zhao top. And so on.
Actually, Riot often does the opposite: Whenever a jungler is going in other positions, they tend to nerf it. They did it with Nocturne for example.
As others have said, it helps newer/offrole players get into jungle more easily. But also, these champs aren’t super overwhelming or unfun to play against in jungle. Some jungle champs would be fine in lane, but some would also be pretty unfun if they were laners. Nidalee top would be really annoying, for example. Nocturne, Graves, Fiddle, Nunu have all seen play in lanes and been really uninteractive. A lot of junglers just statcheck laners, especially mid lane, and use their jungle clearing tools to instaclear waves and roam, which is not very fun.
Something like Sej top or Amumu support would be pretty fine.