New Craftworld player

I’m new to the game and decided to pick up Craftworld for their appearance and lore. I’m having trouble coming up with an army list and any suggestions for list. So far what I have and would like to incorporate are Eldrad, Spiritseer, Illic Nightspear as HQ (might not be right terminology). For troops or groups Ranger, Reapers, Wraiths. For the transport I currently have Wave Serpents and Wraithfighters. Any suggestions on what to purchase or what to run/not run would be absolutely phenomenal. Thank you

Well first, make sure you have the Codex and understand what is and isnt Troops.

Reapers and Wraiths are not troops, they "could" have been troops in the older editions, but in 8th they went back to limited troop choices.

As for what to get? Make sure to have another troop choice (really you want 3, it can be the same 3, just as long as you have 3 units).

After that but the units you like, playing what you like is more important for now.

Amishprn is wise.
Additional dialoguing: You need 3 of any mix/match troops selections (as he mentions). With Illic, you'll likely enjoy Rangers. This edition, the best bang for your buck troops include minimum squads af Rangers or 10man Guardian Defenders with gun platform, IMO. 3 squads of 5 Rangers seems pretty solid if you know you want Illic (I run this setup often).
Dark Reapers are competitive but I keep expected to see a nerf on them. Be prepared. They are a Heavy choice and, if you're going Wraith heavy, the Heavy slot gets filled quickly.
Wave Serpents are transports. But they're so, so good that they are functional tanks, too. I sometimes run them empty just because they're so good.
You mention Wraiths as "groups" so I assume you mean that you like the Wraith Blades (swords or axes) and/or Wraithguard (D-Scythe or blaster version). These are all durable options. There will be a million posts about Blade versions, swords or axes loadout. The answer is: they're equally viable but serve slightly different roles. More hack and slash - go for swords. More meat shield, defenders, go with axes.
Look at Wraith Lords, too. I never, *NEVER* regret fielding one. My local opponents reflect the same notion. Put 1-2 good guns on one, park them in the back as power shooters, keep the Farseer near it (Psyker: Guide) and it's gold. I get 1-3 in nearly every list.
Eldrad is good, but that forces you to pick his stupid Craftworld. I don't particularly love his Craftworld. Wraiths don't particularly love his Craftworld. And, if you have a basic Farseer, you're essentially doubling down on the same benefit. Personally, with the other stuff you listed, I'd swing you to an Autarch or one of the other Aspect HQ's.