In the 1990s, besides the main sets, there were some supplementary sets that were basically just parts collections. At least in Germany, these were offered under the name "LEGO Service", and listed in a small separate catalogue not included in the main catalogue.
An example of such a catalogue can be found here.
These parts collections sets were usually sold in small plastic bags rather than boxes (as opposed to any other LEGO set over here).
What happened to this product line?
- Does it still exist, maybe under a different name? (Obviously, looking for "lego service" brings up many false positives.)
- Is what is currently named LEGO Xtra the successor (even though Xtra seems to have just a tiny number of sets available, some of which aren't even parts, but playmats, and the rest are not just individual parts but actually form (tiny) models such as lamp posts)?
- Was it (mostly) discontinued because of more advanced (read: flexible and probably automated at that) ways of ordering individual bricks?
On brickset, the sets I am thinking of seem to be listed as a "Service Packs" theme, which appears to have existed until 1999, but it's not clear whether or to what extent it was superseded by something else.
