So I'm still considering which forgeworld to go for and I'm really loving the lore about all of them but I'm wanting to know from you,the all mighty lore masters,the fluffiest lists for each sub-faction.I already know Stygies is sneaky and about long range,then Ryza is plasma and melee,but what about Metallic?Or Agrippina?What does a fluffy army for them look like?

Really any advice for list building admech and how to make the different rules work would be much appreciated,I'm decently well versed in 40k in general but I could use some ideas(also someone please explain what "data-tether" as a rule and keyword does,may the Ohmnissiah look upon you with care if you do)