You should definitely look into the "Platinum Breakz" series done by the label Metalheadz. The first two in the series are definitely the best and were made in the 90's. They both feature Lemon D and plenty of other quality artists too.
"The Prototype Years" by Grooverider also features Lemon D among others. This is essential listening for fans of older d'n'b.
Photek's "Form & Function" album is amazing. It has some good remixes by other well known artists on it too. His single "Hidden Camera" is also very good, but it's quite experimental.
"Molten Beats" by Ram Trilogy (Andy C and a couple of other guys) is a solid d'n'b album. Nothing too tricky, just tough beats.
"Wormhole" by Ed Rush & Optical is another one you should look into, as is "Sleepwalk" by Matrix on the same record label.
Other individuals tracks I'd suggest you look out for include the following....
Aquarius - Drift To The Centre / Dolphin Tune
Big Bud - Rafiki / Memories
Blu Mar Ten - Global Access
Boymerang - Still
Danny C - The Mexican / Star / 1, 2, 3 / Klonk
Dillinja - Acid Trak
Dillinja feat. Cybotron - Light Years / Nasty Ways
Doc Scott - Tokyo Dawn
Ed Rush - Skylab / Killamanjaro / Technology (with Nico)
Funky Technicians - Airtight
Hokusai - 12 Till 4
Intense - Breathless
J Majik - Repertoire / Shiatsu / Rotation / Klokwerk
Johnny L - Piper
LTJ Bukem - Music / Horizons
Matrix - Mute 98
Optical - Moving 808's
Marcus Intalex & ST Files - How You Make Me Feel
PFM - For All Of Us / One And Only / The Western
Photek - Complex / The Water Margin
Primary Motive - Venom / S
Red One - Strangled Duck
Seba & Lo Tek - Sonic Winds
Source Direct - The Crane / Artificial Barriers / Snake Style / Exit 9
Uncut - Midnight (MIST Remix)
Usual Suspects - Killa Bees
There's quite a diverse range there. If there's any you like in particular, let me know and I can suggest many, many more.