Those of us who have read the 4th/5th edition Empire army book (and the very late 3rd edition version of the same published in WD 146 and 147) likely remember that back in the day the army list had entries for units of dwarves and halflings. These were organised from amongst local dwarf and halfling populations that had typically been living in the Empire for generations and had adopted the local fashions - such as puff-and-slash cut, colourful clothing and hats with huge feathers on them. However, with the advent of 6th edition the designers wanted to have the list focusing on the human element of Empire, and the halfling and dwarf elements were accessible instead as Dogs of War choices.
Back in the day there was also a decent range of figures to depict such citizens of Empire. In 1992 Citadel released a range of halflings in Empire fashions - this also included the infamous hot-pot launcher! Little earlier Marauder had released a number of suitable dwarves (including a gun crew) as well as a handful of suitably dressed Ogre mercenaries. However, to my understanding these figures have been OOP from GW side for quite a while, and may not be easy to obtain from the second-hand market. However, I have noticed that there are still a number of other fantasy manufacturers that produce figures in suitably stylish clothing to be of interest for people looking to round a proper Empire army with a non-human unit or two (suitable human figures tend to be easier to obtain).
Firstly, there is The Assault Group that has a interesting ranges of dwarves and halflings. The dwarf militia figures come with a range of weapons and little in the way of armour, while the dwarf knights on foot packs could be of interest for those who want their dwarves better armoured. Personally I am most excited of their dwarf guards with two-handed swords - very impressive looking! The halfling range contains a variety of militia with different weapons, as well as an artillery crew (unfortunately nothing resembling a hot-pot launcher) and even a pack of zombie halflings!
http://www.theassaultgroup.co.uk/
Secondly, there is Warmonger Miniatures, which is a sub-branch of Wargames Foundry and has brought back various ranges released by Foundry at some point or another. These include a small range of Swashbuckler dwarves, armed primarily with halberds and various firearms, as well as very fashionable ranges of Mercenary orcs and Ogres/Great orcs (granted, the orcs of Old World for some reason are not particularly famous for adopting human styles).
https://www.warmongerminiatures.com/
I must admit that I have not yet seen these figures in person, nor purchased any fantasy figures from these two manufacturers. However, they are both reputable UK companies, and I have previously purchased various historical products from both of them.
Anybody aware of other fantasy manufacturers that could be of interest for use with an Empire army?