I know there aren't a whole lot of Solara owners here on Tundra Solutions, but for the occasional person who happens to check in here looking for something specific, I thought I'd at least list a few known items by manufacturer for the Gen 2 (2004+).
*Thanks to the guys at SolaraGuy.org for much of the info in this list! 
As new items become available, I'll list them as well.
OEM Toyota Components
Gen 2 Convertible Windscreen (NEW Model '06) # PT906-06041
TRD
Toyota Racing Development
Front Strut Tower Brace (FSTB)
Rear Sway Bar (RSB)
Sports Muffler (PT901-17400-25)
Lowering Springs (-1.4" / -1.2")
Air Filter (Drop-in Rechargeable)
Oil Filter
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Chrome Touring Wheels (18"x8")
Alloy Touring Wheels (18"x8")
Painted Alloy Touring Wheels (18"x8")
K&N
K&N High Performance Air Filters, Oil Filters, & Cold Air Intakes - Official K&N Engineering Site
Air Filter, 3.3L & 2.4L (33-2219)
Oil Filter, 3.3L (HP-1002)
Oil Filter, 2.4L (HP-1003)
Injen
injen_intro
Short Ram Intake, 3.3L (IS2032P or IS2032BLK
CP-e (Custom Performance Engineering)
Custom Performance Engineering -- Welcome
Short Ram Intake MAFci Kit, 3.3L
Tein
TEIN U.S.A. HOMEPAGE
STECH Lowering Springs, 2.4L, should work for 3.3L as well (-2" / -1.9") (SKL68-AUB00)
SS Adjustable Coil Overs, 2.4L or 3.3L (DSL68-KUSS2)
JIC Magic
JIC Magic
Adjustable Coil Overs (not sure what series or part number)
Eibach
Eibach
Lowering Springs (-1.4" / -1.2")
TRENZ
Trenz Home
Billet Bumper Grille; Framed Perimeter; Brushed (2737-TFP)
Billet Bumper Grille; Framed Perimeter; Polished (2737-TFPP)
Billet Grille; Framed Perimeter; Full Replacement; Brushed (2305-TFP)
Mike T Custom Grilles
http://www.cardomain.com/ride/491339
Custom Upper and Lower Mesh Grilles (Brushed, Polished, Painted... see site)
Precision Grilles
Billet Grille (Grill) Insert,Mesh Grilles,Billet Grilles,Billet Aluminum Gas Door,Truck Accessories,Chevy,Ford,GMC,Dodge,Cadillac,Lincoln, Toyota,Nissan
Billet Grille, Polished Finish, 04-06 (807200)
Bumper Billet Grille (807201)
If you find anything else, or are looking for something specific - chime in and I'll hunt it down and add it to the list!
Jeff