Hi! Welcome aboard the WotR train
So with the WOTR flag sheet on the Pendraken site if looks like you've got these flags (listed left-to-right)
First Row:
1. Henry Percy, Earl of Northumberland (Lancastrian)
2. John de Vere, Earl of Oxford (Lancastrian)
3. Henry Holland, Duke of Exeter (Lancastrian)
Second Row:
1. Royal Arms, could be used for any of the kings, Yorkist or Lancastrian
2. Henry Bourchier, Earl of Essex (Yorkist)
3. Humphrey Stafford, Duke of Buckingham (Lancastrian)
Third Row:
1. Henry Bourchier, Earl of Essex (Yorkist), again
2. Richard Neville, Earl of Salisbury (Yorkist)
3. James Butler, Earl of Ormond/Wiltshire (I think), (Lancastrian)
Fourth Row:
1. Thomas de Mowbray, Duke of Norfolk (I think), (Yorkist)
2. Not sure about this one, I
think it might be a livery banner for Edward IV, but the colours on the fields are backwards if that's the case
3. Thomas Courtenay, Earl of Devon (Lancastrian)
Fifth Row:
1. Edmund Grey, Earl of Kent (Lancastrian, then Yorkist after Northampton)
2. Henry VII's standard
3. Henry VII's standard again
4. Richard III's standard
5. William Neville, Earl of Kent (Fauconberg), (Yorkist)
As a heads up, it looks like a lot of the banners on the Pendraken sheet would be for the earlier period of the WotR (the bottom row has Henry VII and Richard III for Bosworth though)
In terms of livery colours (and badges), just about every noble and knight had their own colour scheme for their retinues, so there's plenty of options if you wanted to have a bunch of different people!
The Vexillia livery colours database might help there, it lists the colours left-to-right for each of the nobles if that helps!
https://blog.vexillia.me.uk/2018/09/war-of-roses-livery-colours-database.htmlThe Lance and Longbow Society also do a book of the livery colours, standards and badges if you were looking to buy something on the subject too:
https://lanceandlongbow.com/shop.php (It's under Pub-004 on the list here)
The Perry Miniatures plastic WotR infantry box has a few examples of livery coats and badges as well, if that helps!