Here’s a list of the best perks to select from levels 31 to 40 with the Ghoul Build Guide in Fallout 4:
Level 31 – Bloody Mess 3
Level 32 – Demolition Expert 2
Level 33 – Toughness 3
Level 34 – Life Giver 3
Level 35 – Adamantium Skeleton 3
Level 36 – Mysterious Stranger
Level 37 – Mysterious Stranger 2
Level 38 – Toughness 4
Level 39 – Save
Level 40 – Lone Wanderer 3 + Better Criticals 3