Best speaker under $1K...... used market

I am looking for a 2nd pair of loudspeakers for my basement, and would like some opinions.

I currently have PSB Gold i's and listen to mostly country, bluegrass, and rock. I love the deep bass, but have not listened to many speakers in this range.

My system:
Forte 1a amp
Nad 1600 Pre
Pioneer PD-65 CDP
Kimber 8tc, Silver Streak, PBJ
Triangle Zerius. Best sound I get with these is using - Kimber 8tc. Your forte amp would sound great with these too. I have paid as little as $350 a pair. I have had a lot of speakers (Acoustat, Linn, ProAc, Audiostatic, Altec a7, Ambience, Cain, Lowther, etc.) and these little speakers have been the most satisfying in the long run.

One of the best amps I have used with these is an upgraded ClariT amp from Red Wine. I would love to hear a pair of 70.2 on the Triangles - I think that would be amazing.

Good luck.
Vandy 2Ce Sigs. Full range and they can be had used for under $1000. There are some for sale on A-gon.
Magnepan 1.6
Might want to look at some used Martin Logans
Look for an old goodmans or electrovoice speakers on the ebay. Look for one with 10" woofer. They are fantastic speakers, and they put a shame on so many modern design. But they are ugly.
Would you consider new at $1k to $1.2k ?
If so, Ohm Micro Walsh or Ohm 100 Walsh.
Omni or semi omni directional could fill basement depending on room dimensions. Good review by 6moons on micro walsh.
Used ProAc 1sc, in black. Other finishes will cost you more.
Ditto the Maggies
FYI, Magnepan 1.6 is -3 dB at 40 Hz, Vandy 2CE is -3 dB at 29 Hz. You say you want deep bass, then your best chance is with the Vandy's.
Check out the Klipsch CF4's for sale on this site. They will blow you away with their power and dynamics.
Ditto the Ohm suggestion from Chrisliv. Just got a pair of Micro Walsh Talls and I'm loving them... a tremendous value.
Sound Dynamics 300 TIs, if you can get stands for them (18" high or so). Made in the 1990s and sound way above their price point. Good sound.
Ditto on the cf4s!

I highly resolving, refined and dynamic speaker!
used Maggie 1.6,used Totem Arro,new Ohm Micro Walsh Tall's,new DCM TFE 200,new Wharfedale Evo2 20,new Wharfedale Diamond 9.6,new av123 Xstatic,new Infinity Classia C336,and new Swan D2.1E.
Keep your PSB Golds if you like the bass, otherwise I prefer think Magnepan 1.6 are a bargain in the price range but need to be 3' away from the back wall.

Spend the money instead on your front end, as your CDP is very very long in the tooth!
I would look for a pair of snell c4 or c5's.
Soliloquy 6.3's are great for the price. I had them in my system, was demoing much more expensive (up to $5K speakers at local dealers) and actually preferred my system. I think I paid $1200 for mine used a few years ago, so they can probably be had for around $900-1000 these days. A very full-sounding full-range speaker.