Cool find in Arcana Unleashed. There is a Common magic item called Spell Component Ring which allows you to select one spell where you don't need a hand free to access the material component, as long as said component doesn't cost money or is consumed.

This solves the problem of an Eldritch Knight with Shillelagh (e.g. via Magic Initiate) using Quarterstaff or Club + Shield. The issue was that EKs couldn't use a druidic focus, so they technically wouldn't have a hand free to grab the mistletoe sprig needed for Shillelagh. The Spell Component Ring neatly (and cheaply!) solves that problem.

And no attunement required! Neat find, OP, thank you so much!

Also ruby of the war mage works

The issue was that EKs couldn't use a druidic focus, so they technically wouldn't have a hand free to grab the mistletoe sprig needed for Shillelagh

To be clear, they were always able to use Shillelagh. This just lets them use it while holding a shield.

Yea but that requires attunement

Very true!

I don't think this interaction works. Shillelagh still has a somantic component and the ring specifies that only the material component is handled by the ring.

Good catch, but that part is solved easily enough with War Caster.

Ruby of the War Mage is in the 5.5 DMG

This is correct.

I just fear some people might see this thread and try to get one over their DM when they aren't firm with the component rules to save a feat that isn't otherwise very useful for an EK.

The PHB recommends starting with one Common Magic Item at level 3, so this is a great solution. You still need a hand free to use the Somatic components though, so you'll have to take Warcaster at level 4 and only attack with True Strike before then. The neat thing is that you can also do this on a PSI Warrior by taking the new Fighting Style and swapping it out for Dueling at Level 4.

Sadly, the Psi Warrior gets far less of a benefit from War Caster than the Eldritch Knight, as they don't learn any spells until level 18, and picking up True Strike and/or a blade cantrip doesn't give much flexibility on species and origin feat.

but the ruby requires attunement that could go towards other cool magic items, while the ring does not

I don't agree with the feat not being very useful for Eldritch Knights. Casting True Strike with Reactive Spell is a strict damage increase on a Shillelagh build after level 5, and even more so if you play with Legacy Content and can cast Booming Blade. Getting Advantage on Concentration checks is great for keeping up a lock-down spell like Sleep or Hold Person or on spell that buffs yourself. I think Warcaster is more than worth it even if you don't need the Somatic components

ofc the new ring is better for the EK + Shilleagh