Not sure if this is a good seed by others standards, but it is for me. Just discovered this the other night.

What I found noteworthy is that all 5 bosses and the trader are in a very close proximity to the spawn island. 3 of the bosses are on the starting island itself (Eithkyr, Elder and Moder).

https://valheim-map.world/?seed=YzMGp44vCs&offset=192%2C-800&zoom=0.322&view=0&ver=0.207.20