I love these pens, so I have been buying them off-and-on, sometimes even when I already have the same pen. The result is a "collection" that is uneven. I still have to obtain the more interesting limited editions (such as Hunting and Austria and the newer ones), so I am on the lookout. The following is in no particular order; it probably reflects the chaotic nature of my collection.
1931 Limited Edition (Vintage 1997; 5000 pieces)
No 504
1931 White Gold Limited Edition (Vintage 2000; 1931 pieces)
No 1247
1931 Toledo (Vintage 2003; 1100 pieces)
1935 Limited Edition (Vintage 1998; 4000 pieces)
No 855
1935 Blue Limited Edition (Vintage 2001; 1935 pieces)
No 549
25 Jahre Nord/LB (Vintage 1996; limited to 6920 pieces)
730 (Vintage 1993-present)
750 (Vintage 1988)
760 (Vintage 1988)
Blue Planet (Vintage 2006; 540 pieces)
No: 372
Caelum (Vintage 2005; 580 pieces)
No: 144
Classic (New Line); also known as D380/381 (Vintage 1992-1995)
Concerto (Vintage 1996; 4000 pieces released)
Evolution of Script (Vintage 2007; 90 were produced)
No: 284
Gaudi (Vintage 2002; 1000 were produced)
Golf Set (Vintage 1996; 2000 sets were released in addition to 2500 FPs)
Hercules (Vintage 2004; 800 were produced)
No: 601
Hunting (Vintage 1994; 3000 were produced)
Toledodo
700
710
900
910
Wall Street (Vintage 1995; total 4500 pieces: 2500 FP & 2000 sets)
3512
Kuala Lumpur (Vintage 1998; 888 pieces)
No: 373
M200 (Vintage 1990's)
M250
M300 set (Vintage 1997)
M400 /R400
M425 (Vintage: 2005)
M450
M600/K600
M620
Berlin (2001)
Stockholm (2001)
Madrid (2002)
San Fransisco (2002)
Chicago (2003)
New York (2003)
Athens (2004)
Piazza Navona (2004)
Place de la Concorde (2005)
650 (M and K)
800 (The green FP is old style with "Germany" imprint but metal cap insert; the set is even older style with "W. Germany" imprint. The last one is the 800 demonstrator.)