Lots of good suggestions if a little heavy towards Pilot/Iro. for my tastes. Nothing against them, liked the ones I have tried, but don't own any beyond samples.
Saddle Brown - a nice mid shading brown - I have it in a TWSBI 580 with a B stub nib
Steel Blue - - turquoise family In a Pelikan M150 right now
Classic Red - good true red
Blue Black - not my favorite blue black, but I do like it and it behaves well
Sherwood Green - nice dark green
Apache Sunset - fun, playful happy ink. I think it is quite good for correspondence and journals. I have in a TWSBI Eco 1.1 stub right now
Black - not bad, I don't use it much. It came in a set I got from Goulet. Leuchtturm notebook, Pilot Metropolitan and Noodlers Black. It is bulletproof. I don't often use black. But generally well behaved
Eel Blue - this I got as a PIF - not a bad ink. I like the color, but almost like Serenity Blue better.
54th Massachusetts- bulletproof blue black, interesting color. Not sure why I don't use it more.
Blue Black - My favorite Blue Black.
Waterman Serenity Blue - plays nice in all my pens,
Levenger Pomegranate - one of my favorite reds. Like the rind of the fruit. No longer available.
Iron Gall Turquoise - a beautiful turquoise that is very wet for a IG ink.
Azure of Sky - interesting blue. My bottle is very dry. Not sure if it is mislabeled, a bad batch or what. The IG Turquoise is wetter.
Daintree Green - beautiful mid to bright green
Uluru Red interesting mid red.
Sydney Harbour Blue - almost blue black and sheens like crazy
Barrier Reef Blue - beautiful blue and with a gorgeous red sheen.
Red Cashmere- a dark red that almost looks like Pomegranate sometimes. A pre-production ink that never made it to production
Green Cashmere- an interesting murky/mossy green (some might call it green/black). Another pre-production ink that didn't go into full production.
Akkerman - (never had more than 30 ml)
Voorhout Violet - this is an interesting purple. I have it in a Esterbrook J with 9550 (EF) right now.