Many of the characters in BFDI, depending on the object, have had their own 'OMG' moments in which they state "Oh my" and then something relevant to their "God", which is something related to their object form, for example Pin's "god" is a Pin Factory, which created her.
Some characters even have 'WTH' (what the heck) moments, like Snowball (What The Flake) and Match (What The Wood Sickle).
FlowerIn Insectophobe's Nightmare 2, Flower states her OMG as "Oh my Gardener!"
Blocky is yet to have an OMG moment.
Woody is yet to have and most likely never will have an OMG moment, since he doesn't talk much.
Teardrop will probably never will have an OMG moment since she can't talk.
Golf Ball is yet to have an OMG moment. But if there is one, it might be: "Oh my dimples!" or "Oh my Place Where Golf Balls are Created", or for short, "OMPWGBAC!"
Coiny's OMG moment was said twice as "Oh My Mint!" or OMM for short.
Snowball's OMG moment was said at the biggest and final rejoining ceremony of Season 1 as "Oh my Snowflake!"
Match's OMG moment is "Oh my like, Woodsicles!" though this is unsure of and vague, especially after she said "OMQ" and "OMZ" in Season 1. Match also has had the most OMG'S.
David is yet to have and probably will never have an OMG moment, as he is usually seen saying his only catchphrase, "Aw, seriously?" or "NO!"
Pencil has an OMG moment, and it is "Oh my Tree" because wood comes from trees, and Pencils are made with wood. It has been used twice in both the BFDIA 6 Deleted Scenes video as well as Welcome Back.
Rocky was planned to have an OMG moment, but then jacknjellify decided to take away his ability to speak. It remains unknown if Rocky will ever say OMG.
Bubble's OMG moment is "Oh my Bubble Blower!", sometimes shortened to "OMBB!"
Nickel is the only character to say "Oh my God", in Episode 5d: It's a monster
Firey's OMG moment is "Oh my Oxygen!", used once after getting barfed on.
Firey in multiple episode's has said "Oh my gosh"
In BFDI Is Back, he used "Oh my spark" once for his OMG moment after finding that Bfdi is back.
Book's OMG moment is "Oh my Word", used twice.
Fries' OMG moment is "Oh my Potatoes", used twice.
In Welcome Back, Fries's other OMG moment is "Oh my tater", used once.
Gelatin's OMG moment is "Oh my collagen", used once in a video including BFDIA 6 deleted scenes.