I found a small SMP server called Mace through a friend and it feels really chill.
It does not have a lot of players right now but the staff take care of it really well. It feels like a nice place to just play and hang out so I would recommend giving it a try.
Mace SMP The Chill Small Server
GG.MINEWIND.NET New Server IPCozy Semi-Vanilla Survival Forever World
This is a peaceful Survival server that feels old school and made for builders who want a calm place to stay for a long time.
It is all about playing slow and doing things the classic way with natural progression and vanilla gameplay coming first.
There is no PvP so it is cooperative and chill. The world is meant to last forever with no wipes. It also stays fair with no pay to win stuff or cash grab mechanics.GG.MINEWIND.NET New Server IP