Speakers for Luxman LX-380

Most likely a high efficiency speaker such as Klipsch, JBL, ZU Audio etc.

Right but looking for specifics.

I own many speakers. The ones that sound very good to my ears using my Allnic T-1500 300B Integrated are (in no specific order) Klipsch Forte III, JBL 4319, Von Schweikert 99 with Super Tweeters, ZU Audio Union Six Supreme, and Montana EPX speakers. Different flavors but all sound very good.

OP,you need to provide a lot more information...What is your budget?How big is the listening room?What are the acoustic properties of the room,ie:bare sheetrock walls/lots of glass/hard floors or carpet/lots of overstuffed furniture or barely any?What kinds of music do you listen to & how loud do you listen?Will you add even a basic amount of acoustic room treatments at a later date?
With your amp having only 18wpc.@ 8 ohms/20wpc.@ 6 14wpc.@4 ohms you want something that doesn’t drop below 6 ohms throughout it’s entire operational frequency range..
If you have a smallish room,say something around 12’ x 14’ (+-2’),listen to a variety of music at normal levels with an occasional rock out mode,my recommendations without knowing anything else but your amp,I would say ProAc Response D2,Harbeth M30.2Xd’s,Spendor Classic 3/1 or Reference 3a DeCapo with the factory available silk dome tweeter instead of the Beryllium version...