So here is the unit list - it is from P&M TW for the MTW, so more units can be added as well.

The names are in national languages, some units will be also available as mercenaries, regional troops or for several factions.
Units unique for one faction only are marked with #




FOR MANY FACTIONS or all of them ( cultures)
Artillery:
Organ Gun,
Mortar,
Demi-Culverin,
Culverin Crew,
Mercenary Cannon,
Serpentine,
Siege Cannon,

Infantry:
Archers,
Urban Militia,
Town Militia,
Pavisiers,
Pavise Arbalesters,
Arquebusiers,

Muslim Feudal Levy - only Muslim factions ( except Tatars), a typical 'cannon fodder',

Wagon Infantry - hard to create, maybe a form of field fortifications.

Cavalry:
General - different for different cultures,
Lancers - basic heavy cavalry from late Medieval,
Demi-Lancers - for western factions,
Mounted Crossbowmen,
Eastern Lancers - lighter than western lancers,
Mounted Arquebusiers,

ADVANCED:
Line Infantry,
Grenadiers,
Regimental Cannons,

DISMOUNTED CAVALRY - if possible
Nobles - several eastern european cavalry units,

Dismounted armoured cavalry - eastern european and ottoman heavier cavalry,

Knights - or rather sword & buckler - several western european cavalry units shpuld dismount into them, also available as an infantry unit for some factions ( e.g. the Knights);

Dismounted Cavalry - modern, western cavalry units will dismount into this;

REBELS
Fanatics,
Rebel Marksmen - experts at hiding,
Peasants,
Peasant Guerillas - expert at hiding,

REGIONAL
Czeremisi - VOLHYNIA AND VOLGA-BULGARIA
Uskok - DALMATIA
Musketyri - BOHEMIA
Wallon Pikemen
Wallon Corselets - 'corselets' so heavy, armoured pikemen,
Wallon Musketeers


MERCENARIES - many more units will be available as mercenaries e.g. Cossacks, Scots, Swiss etc. But here are the units which will be available as mercenaries ONLY,

Infantry------>
Lancknecht Pikemen,
Lancknecht Halbardiers,
Lancknecht Armoured Pikemen,
Doppelsoldner,
Lancknecht Arquebusiers,
Mercenary Musketeers,
Mercenary Pikemen,
Italian Arquebusiers - IN ITALY
Italian Corselets
Italian Pikemen

Cavalry---->
Free Lancers,
Mercenary Dragoons,
Reiter - IN GERMANY
Mercenary Cuirassiers
Albanian Stradiots - IN ITALY


THE OTTOMAN EMPIRE

Infantry------->

'cannon fodder'
Sekbans#
Azebs#
Tüfekchi # - musket armed, so better;

brigands & pirates
Martolos - greek bandits,
Levends #
Panduks - marksmen,
Ta'ifat Al Ru'sa - algerian pirates,

Jannissaries
Zirhli Nefer# - heavayinfantry, polearms;
Okchu Yenicheri#
Tüfekchi Yenicheri#

Cavalry----->

border cavalry, also Ghazi
Akinji#
Deli#

feudal cavalry
Timarli Sipahi#
Jebelü #

elite cavalry
Kirmizi Bayrak # - majority
Ashaghi Bölüks # - guardians of the Prophet's Banner
Sari Bayrak# - Sultan bodyguards,

balcan auxiliary, heavier cavalry, probably there is a better name for them I'll check
Voynuk


GEORGIA - #ALL

Infantry---->
Aragvlebi
Mtiulebi
Kveiti Meomrebi
Metopheni

Cavalry------>
Elite Mkhedrebi
Shubosani Mkhedrebi


RUSSIA - #- ALL

Infantry---->

musket/arquebus armed
Pishchalshchiki
Streltsy
Soldaty
Vybranniye Soldaty

pikemen
Streletskiye Kopeyshchiki
Kopeyshchiki
Vybranniye Kopeyshchiki

others
Dismounted Ryndy
Opolcheniye

Cavalry----->

feudal cavalry
Pomestnaya Konnitsa
Znat
Ryndy

reformed
Reytary
Draguny

russian copies of Polish cavalry types
Gusary
Stremenniye Kopeyshchiki

others
Stremenniye Streltsy
Sluzhiliye Kazaki
Tatarskaya Konnitsa


MOLDAVIA

infantry--->
Razesi
Calarisi#

cavalry-->
Oastea Mare Cavalry
Wallachian Cavalry
Wallachian Horse Archers
Oastea Mica Viteji
Oastea Mica Boyars

POLAND - #-ALL EXCEPT "Lisowczycy" who are mercenaries,

Cavalry---->

professional
Petyhorcy,
Pancerni,
Husaria - Winged Hussars
Kozacy- armoured, ancestors of Pancerni;
Strzelcy,
Dragoni,
Rajtarzy,
Tatarzy - Polish/Lithuanian Tatars,
Wolosi,

noble levy
Szlachta
Kresowa Szlachta

mercenaries, for Poland 'normal' unit
Lisowczycy


Infantry------>
Piechota wybraniecka

reformed
Piechota lanowa
Muszkieterzy
Pikinierzy

COSSACKS

Infantry---------->

Ukrainian Peasants - 'cannon fodder', numerous and cheap;#

Molodyki - young Cossacks, light pikes, 'cannon fodder';#

Zaporozhye - 'core' infantry, good musketeers;

Serdjuks - elite musketeers;#

Plastuny - Cossack foot scouts, hide everywhere, marksmen;#

Harakterniki - cossack legendary warriors, hide everywhere, hard to get;#

Cavalry-------->

Storozha - Cossack horse scouts, hide in long grass;#

Reyestrovie - basic cavalry, average quality;

Dzhura - cossack bodyguards, god quality cavalry;#

SWEDEN - #ALL

Infantry------->

early
Svennar
Dalkarlar
Kungliga Majestäts Drabanter

reformed
Musketerare
Pikenerare
Svenska kommanderade musketörer
Kungliga Maj:ts garde och livregemente

Cavalry------>
early
Landsryttare
Svarta Ryttarna

reformed
Upplands ryttare
Dragoner
Smalands ryttare
Hakkapeliitta - Finnish cavalry

PORTUGAL - #ALL
Piqueiro Ligeiro
Marinheiro Portugues - Portuguese sailors

arquebusiers on camels !
Arcabuzeiros de Goa

FRANCE #-ALL

Infantry ---->

early
Royal Swiss Pikemen
French Royal Foot Arquebusiers
French Royal Foot Pikemen

Enfants Perdus - French Forlorn Hope

reformed ( Richelieu)
French Musketeers
French Pikemen"}
Mousquetaires du Roi

Cavalry---->

early
Gendarmes de la Garde
Argoulets

reformed
French Light Cavalry
French Heavy Cavalry
Mousquetaires du Roi - elite, dismountable



THE NETHERLANDS

Infantry--->
Watergeuzen#

pikemen
Piekeniers met rondas #
Pikeniere#

musketeers
Musketiere#

Cavalry---->
Ghemeijn ruyteren#
Gheappoicteerde curassiers#

HAPSBURG - AUSTRIA, HRE

Infantry---->
Musketiers
Piekeniers
Verlorne Haufe - Forlorn Hope !
Rondartschiere#
Fortified Musketeers#

Cavalry ------>
Croats
Croat Grenzers
Empire Cuirassiers#
ImperialDragoons

LIVONIAN CONFEDERACY ( OR TEUTONIC ORDER)
Courland Reiters

CRIMEAN KHANATE ( Tatars)
Kirim Suvari# - elite
Izci Tatarlar - scouts, hide in long grass !!
Kipchak Asker#
Atli Tatarlar
Nogay Asker#
Tatars with arkans# - slave hunters

Infantry
Keffe Bekci# - crimean Jannissaries

SPAIN #-ALL

Infantry----->
Rodeleros
Guardia Tudesca
Alguaciles - Spanish town guards

projectiles
Arcabuceros
Ballesteros - albalesters
Forrajeros
Mosqueteros
Mosqueteros - REFORMED

pikes
Corseletes
Picas Secas
Piqueros
Piqueros - reformed unit

special
Encamisados - hide everywhere,

Guardia Real - elite

Cavalry---->
Archeros
Celadas
Celadas - later period
Dragones
Herreruelo
Nueva Guardia


DANEMARK
Infantry ----->
Snapphanar# ambush experts

Cavalry ---->
Musefanen#
Rostjenste#
Nationale Ryttere#


SWITZERLAND
Swiss Pikemen
Swiss Armoured Pikemen#
Swiss Halberdiers

THE KNIGHTS
infantry
Order Militia#

VENICE, GENOA
infantry
Scapoli - marines,

FLORENCE
cavalry
Bande Nere# - the Black Band


HOUGENOTS

cavalry
Millers#

HUNGARY - will be revised thanks to the help of Speiz_Bankurt
Infantry---->
Haiduks
Harami

Cavalry---->
Szekely Hussars#
Hungarian Hussars#
Rac


SCOTLAND
Highland Clansmen#
Scottish Archers
Scottish Pikemen
Scottish Musketeers
Montrose's Musketeers# - veteran unit able to beat enemy cavalry in melee;

IRELAND

Infantry------>

Omacach - elite melee infantry;

Enniskillen Fusiliers - elite musketeers, 'bulletproof vests';

Oaghancocharan - elite marksmen and ambush fighters;

Kernbannal - basic rebels, javelins;

Galloglaidh - axe wielders, elite melee unit;

Cavalry------>

Hobilars - good quality lancers with javelins;

Taghhoba - good quality mounted arquabusiers;


EGYPT - some units also for the Ottomans,

Infantry------->
Mamluk Handgunners#,
Ashirs - syrian militia,

Cavalry------>
Mamluk Horse Archers#
Saharan Cavalry
Mamluk Cavalry

Camels
Bedouin Camel Guns#
Bedouin Camel Warriors

ENGLAND

Infantry------>
Longbowmen#
Sprinkler Men#
Billmen#
Trained Band Billmen#
Trained Band Musketeers#
Trained Band Pikemen#

cavalry--->
Border Reivers

New Model Army-->
Ironsides#
New Model Army Musketeers#
New Model Army Pikemen#


Saxony LifeGuards#

BAVARIA
Bavarian Black Cuirassiers - Pappenheimer's cavalry

BRANDENBURG

HANSA

Hansa Town Militia

NAVARRAE



I will edit this post if something serious will be changed.

ALL these units are already available in the MTW edition of this mod - check the thread in the Engineers Guild and my sign for downloads.
The units appear in 0.7 beta pre-release for MTW.

ALL these units are known in details ( mostly), which allows recreating them in the RTW engine mod.

Persian and African ubits will be added later.

Regards Cegorach/Hetman