There are a ton of Seal/ Crest guides but this is the most logical I found and it seemed to work very well:
The KoC site says that the location of Crest is a random drop, with the majority of each crest type falling on a particular wilderness type. They recommend that the story of Arthur and his Knights give clues concerning their lives and upbringing. Below, I have listed the Knights and some basic facts about each knight along with recommendations that these facts may give as clues. These are only suggestions. Good Luck!!
King Arthur- Born at Tintagel (Hills?) Raised by Sir Ector (grasslands?) Camelot built atop the tallest HILL(?) in Cornwall.
Morgana le Fey- Arthurs sister and mother to Mordred. born in Cornwall (Hills?) married to King Lot of Orkney (grasslands?)
Mordred- son of Arthur raised in Orkney (grasslands?) stronghold in the WOODS(?) Killed by Arthur at Camlann on Salisbury PLAINS(?)
Ector- Arthurs foster father Noble farming family (grasslands?)
Kay- Foster brother of Arthur Noble farming family (grasslands?) most famous deed, killing the giant and freeing the captives from a LAKE(?)
Lancelot du Lac- name means of the LAKE(?) raised by Vivienne, the Lady of the LAKE(?) most famous deed, killing the Copper Knight at Delorous Guard (MTNS?)
Galahad- Son of Lancelot(LAKES?) raised in a nunnery (MTNS?) like Arthur, pulled his sword from a stone (HILLS?)
Percival - raised in the WOODS(?)
Gawain- Arthurs nephew/ brother of Mordred Born in Wales (Hills and Woods?)
Bors de Ganis - only Knight to return from the Grail Quest Known as a great horseman (PLAINS?)
Bedivere - this guy is difficult, clues can lead anywhere. He was a wandering knight, so was known to be anywhere, as his life shows. educated in a monastery in MTNS(?) after Arthurs death, returns Excalibur to Vivienne (LAKE?) lives the rest of his life as a hermit in the WOODS(?) buried at Tryfan HILL(?)
thats about what I gather from the Tales of the Knights of the Round Table. Try it if anyone wants to add to it please add below here: