The mods I won't play without;

BepInEX mod engine. was easy to install and use

QuockConnect; connect to shared servers with a single mouse click from main menu
https://www.nexusmods.com/valheim/mods/193
https://valheim.thunderstore.io/package/bdew/QuickConnect/

Better Exploration; area revealed by exploration increased
https://www.nexusmods.com/valheim/mods/1204

FarmGrid; never plant your onions too close together ever again.
https://www.nexusmods.com/valheim/mods/449
https://valheim.thunderstore.io/package/Nexus/FarmGrid/

BlastFurnaceFix; blast furnace can process ALL metals as it should
https://www.nexusmods.com/valheim/mods/142

UnrestrictedPortals; metals through portals, all or just user defined
https://valheim.thunderstore.io/package/xAfflict/UnrestrictedPortals/
https://www.nexusmods.com/valheim/mods/61

Makes later game Iron grinding MUCH less grindy. I already did my penence and played the game through to Yagluth twice without the Portal mod so I feel zero guilt at using the mod now for solo replay.

NOTE: all these mods are client side but will work on shared servers without the server being modded last I checked.

If Iron Gate ever makes the game so I can't use the above mods I will stop playing.

I hope this was useful :D Good Hunting o/