Fall Damage is a form of damage you can take by landing from great heights. This damage can be reduced by any means listed below, but there is a limit to which you can fall from... so jump responsibly!
You can remove all non-lethal fall damage by wearing the Silvercat Ring, or by using the Spook spell. The highest known ledge that you can fall from and survive is the broken railing next to the first Bonfire in the Undead Settlement (called "Foot of the High Wall"). Keep in mind that running and jumping off this bridge will kill you, thus it is the highest height to survive falling from!
Fall damage is calculated in a percentage rather than a flat amount of damage (so having more Vigor will not increase the height you can survive falling from). This percentage takes into account the following Stats: Dexterity, Vitality, and current Equipment Load (the percentage is also based off of your embered state[Max HP + 30%]). Keep in mind that the current equipment load seems to take into account the number, not the percentage (so having 10% with 1,000 Equip load will be different from 10% with 10 Equip load). Dexterity and Vitality both have caps at which leveling them will no longer increase the height you can survive falling from. Vitality gives more height per level than Dex, so that is more useful! (as useless as this data is)
The only useful application for this (that I know of) is for reaching Irina of Carim without paying the measly 1,500 Souls for the Grave Key. This is only useful for some speedrun someone may decide to come up with (like unlocking every NPC). This fall is survivable with 0 Equip Load, 8 Vitality, and 11 Dexterity (with 8% or more to spare) so you may be able to survive with any of the starting Classes without leveling any Stats!
Feel free to edit this page to make it look fancy or to add more of your own finds!
All the information I gathered was from "Limit Breakers" youtube video titled: "Fall Damage, Silvercats and Exploding Kneecaps - Data Talk" (sadly I cannot link the video due to reasons... IDK why)