London was by far the biggest of the Assay offices.  Most Antique Georgian silver sugar tongs (approximately 87%) were assayed in London and so the list of makers is very long.

This means that just by specialising in collecting London made tongs, the full range can be collected.  If you decide to collect London made tongs, you can narrow your range down through a variety of methods, (such as collecting particular date ranges, styles or makers or groups of makers).  There are also some very rare London makers, so just choosing London work does not mean they are "common".

There are a few makers that specialised in "flatware" or sugar tongs in particular.  There are also some shops that were simply prolific in making all kinds of silver.  The most well known of these are the Batemans.  You can see work by all of the Bateman family on this web-site.  This is certainly a good suggestion for a collection and there are probably many collectors who specialise in Bateman work, (not just sugar tongs).