Topps never restarted the numbering. Card 1 is Nasty Nick in June 1985 and card 620 closes the fifteenth US series in 1988, and every card in between is part of one long run. Each number has an a and a b version, the same painting with a different name, which is why there are two kids for every number.
Here is how the run breaks down, by the numbers printed on the cards.
| Series | Year | Numbers |
|---|---|---|
| OS1 | 1985 | 1 to 41 |
| OS2 | 1985 | 42 to 83 |
| OS3 | 1986 | 84 to 124 |
| OS4 | 1986 | 125 to 166 |
| OS5 | 1986 | 167 to 206 |
| OS6 | 1986 | 207 to 250 |
| OS7 | 1987 | 251 to 292 |
| OS8 | 1987 | 293 to 334 |
| OS9 | 1987 | 335 to 378 |
| OS10 | 1987 | 379 to 417 |
| OS11 | 1987 | 418 to 459 |
| OS12 | 1988 | 460 to 500 |
| OS13 | 1988 | 501 to 540 |
| OS14 | 1988 | 541 to 580 |
| OS15 | 1988 | 581 to 620 |
John Pound painted every front in the first two series. Tom Bunk, who had been drawing the card backs, joined him on the fronts with the third series, and in our Card Index Pound has 54 of the base cards in OS3 to Bunk’s 23, with Mae Jeon credited on four. James Warhola arrives in the sixth series with 20 cards. By the eleventh the three are almost level: 28 for Pound, 28 for Bunk and 26 for Warhola. Then Warhola fades out, with two credits in OS14 and none in OS15, which closes on Pound and Bunk, 56 cards to 32.
Those middle series were also the years of the lawsuit. Topps was sued by the owners of the Cabbage Patch Kids in 1986 and settled in February 1987, agreeing to redraw the kids so they no longer looked like the dolls. The later series show it, and the story of the case is in our feature on the lawsuit.
The run did not quite stop at 620. A sixteenth series, numbered from 621, came out in Europe, and the art made for it became All-New Series 1 in 2003. Both are in the Card Index, along with every Original Series checklist.