I think that I might have eased the Deli/Djeli irregular cavalry problem for myself at least, using older Baccus cossacks.  I was given an unpainted Russian Napoleonic army a few years ago. (The army had been in the previous owner's painting queue for years.)  It had a couple of units of cossacks that I didn't paint at the time, because there were more than I needed.  They have taller hats than the current ones, presumably modelled on tall fur hats.

For Yoruks (Tatars) I am intending to get some "NRU33 - Tartar Cavalry" from the Napoleonic Russian range when I can do my next order.  I have a feeling that when the Russians grabbed some of the territory that housed Tatars, the Ottoman Empire rehomed quite a few in what is now eastern Bulgaria and Rumania, but then was part of "Turkey in Europe".  Might get some Arab cavalry at some point, but I have an order in the pipeline and nearly £50s of stuff to get for the order after that that I can't place yet.

https://www.deviantart.com/donkuchi/art/Untitled-808261227

I used 18th Century Ottomans for my army.  I used Pancerni, Janissaries, and Levant Infantry, as well as levant artillery

Below are my suggestions for an Ottoman Army of the late 18th and early 19th Centuries. Please note that bayonets should be removed for many of the troop types (Segban didn't use them but infantry trained as European-type Light or Line Infantry often did.) For many of the infantry types, the colour parties are inappropriate.

Edit: One new paragraph below this.

Be aware that most Ottoman troops did not have a complete uniform as such, just similar tendancies and maybe one or two distinguishing features such as the Janissary headress. Feel free to play mix and match. (My Bostancia guard and Nizam-i-Cedit are uniformed, of course.)

Command

OTT19 – OTT19 – Ottoman Generals – for Ottoman Generals – not used yet but intended for next order

CMA05 – Mahdist Emirs – My current command figures. Probably okay for Mamelukes

Cavalry

Sipahi and Mameluke Cavalry

CMA03 – Mahidist cavalry – most of my Sipahi and Mamelukes

OTT17 – Armoured Cavalry – probably what I used for armoured Sipahi and guard cavalry

OTT15 – Siphi Cavalry, Charging – not tried but look promising

OTT16 – Sipahi Cavalry, Stood – not tried but look promising

Irregular Cavalry

NRU33 – Tartar Cavalry – used for my Yoruk (Tatar) Irregular Cavalry

OTT18 – Tartar Cavalry – for Yoruk (Tatar) Irregular Cavalry – not tried but look promising

GNC01 – Cossack Cavalry – possibility for Deli – not tried, but look promising

[I used older Napoleonic Cossack figures for my Deli Cavalry]

Infantry

Guard etc.

CEG01 – Egyptian/Sudanese Infantry, Formed – White Uniform - for my Nizam-i-Cedit and Bostancia

Janissaries

OTT01 – Janissaries, musket – formed – for most Janissaries

OTT07 – Levant infantry, musket – formed – for Egyptian or other African Janisaries

Arnauts and Similar

FPF08 – for Light Infantry and Trained Line (without colour parties) – have packs, otherwise could be Segban

ACW09 – Zouaves, Formed – probably what I used for Segban (without colour parties)

ACW10 – Zouaves, Skirmish – probably what I used for European and Anatolian Jaegers

CMA01 – Mahdist Infantry – Spear, Sword, Shield – Could probably be used for the general Muslim levy

CMA07 – Mahdist Riflemen – African Jaegers

Artillery

OTT14 – Levant Artillery – for Guns

CMA06 – Mahdist Artillery – possible alternative for artillery – not tried

@I am a spambot, thanks for this very interesting post !

We are considering recruiting an Ottoman army to play the new rule BONAPARTE, le wargame... French rule made for 6mm!

@Peter do you except some new product about napoleonic Ottoman figures?

I have painted and based my "OTT19 – OTT19 – Ottoman Generals". Despite my painting they look good, and similar to some of the illustrations in C. Flaherty's "The Napoleonic Ottoman Army Uniforms, Tactics and Organization". I will use them for Ottoman armies raised by, or on behalf of, the Sultan. The "CMA05 – Mahdist Emirs" work well for provincial armies such as the Mamelukes, and Ali Pasha of Janina's forces, in my opinion.

Great question — you're right that Napoleonic Ottomans are pretty rare on the tabletop, so proxy options are definitely worth exploring.

Early 18th century Ottomans can work fairly well, especially for irregulars like bashi-bazouks or provincial levies, since their dress and equipment didn't change dramatically. However, for more regular units — like the Nizam-i Cedid (the "New Order" troops introduced during Selim III's reforms) — you'll want figures that reflect their more westernized uniforms, closer to European line infantry of the time, though still with distinct Ottoman elements like turbans or fezzes.

A few suggestions:

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https://www.medipakiet.pl/blog/skoki-rozwojowe-jak-przegiegaja-i-jak-je-rozpoznac/

• Gripping Beast and Wargames Foundry have decent ranges for earlier Ottomans that could be repurposed with some minor tweaks.

• Perry Miniatures doesn’t have dedicated Napoleonic Ottomans, but some of their Egyptian or even Indian troops can work as proxies with conversions or creative painting.

• Brigade Games has a few figures in their Napoleon in Egypt range that might serve for Mamluks or other auxiliaries.

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Always good to hear more suggestions! Must admit that I wasn't aware Gripping Beast, Wargames Foundry, Perry Miniatures and Brigade Games did 6mm figures. Are they compatible with Baccus figures? 6mm must be getting more popular.

Would the new(ish) Rapier ACW Zouaves in Turbans or Fez work to some extent?

Not seen them in real life, only on the Rapier Website. Probably do for Balkan or Anatolian locally-raised infantry (which is what I use the Baccus ones for). You would want to paint them differently, because they wouldn't be uniformed, so various colours of coat and trousers. If possible, paint them as if it looks as if they have a white or pale shirt with a darker jacket or coat. You would probably want to remove the bayonets, unless you wanted troops trained by officers from more formal armies, or troops with a lot of experience against the Russians.