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).
Flower
In Insectophobe's Nightmare 2, Flower states her OMG as "Oh my Gardener!"
Spongy
Spongy’s OMG moment was in Today's Very Special Episode where he said "OH MY SOAK!" in reaction to Beep’s creation. [citation needed]
Woody
Woody is yet to have and most likely never will have an OMG moment, since he doesn't talk much.
Pin
Pin's OMG moment was "OMPF", which meaning was revealed in The Long-lost Yoyle City as "Oh my Pin Factory!"
Needle
Needle does actually have an OMG moment, but it was hidden due to an elimination layer glitch. It remains unknown, but it could possibly be "OMNF" similar to Pin's "OMPF"
Teardrop
Teardrop will probably never will have an OMG moment since she can't talk.
Golf Ball
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
In Season 1 Coiny's OMG moment was "Oh my Midge" or OMM.
Coiny's OMG moment was said once in Why Would You Do This on a Swingset as "Oh My Mint!" or OMM for short.
Snowball
Snowball's OMG moment was said at the biggest and final rejoining ceremony of Season 1 as "Oh my Snowflake!"
Match
Match's OMG moment is "Oh my like, Woodsicles!" though this is unsure of and vague, especially after she said "OMQ" and "OMZ" in Barriers and Pitfalls. Match also has had the most OMG'S.
In Cycle of Life, she may have said "OMT", which may mean "Oh my Tree" but it may have just been an "OMG". Closed Captions say "OMG", but they weren't set by hand.
Match is the first to say OMG or a related word like OMQ, OMW, OMZ more than 10 times even 20 times.
Eraser
Eraser says "Oh my God!" in "Getting Teardrop to Talk".
Pen
Pen said "Oh my gosh" in Return of the Hang Glider, as well as Tennis Ball in Crybaby!.
In Fortunate Ben, when Liy change her appearance Pen said "What the flip!".
Yellow Face
Yellow Face said "Oh my gosh" in the Non-Slip Shoes So Ha commercial, and the Announcer.
Tennis Ball
Tennis Ball's OMG moment was "Oh my Place where Tennis Balls are Created!" or "OMPWTBAC!" when he found the wall teleporter in IDFB 1.
David
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
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
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
Bubble's OMG moment is "Oh my Bubble Blower!", sometimes shortened to "OMBB!"
Also in Gardening Hero, she said "Oh my Go(i)sh".
Leafy
Leafy's OMG moment is "Oh my Tree!", used once in Crybaby!.
Also in Barriers and Pitfalls Leafy said "OMZ", no one knows what it stands for though.
Nickel
Nickel is the only character to say "Oh my God", in Episode 5d: It's a monster
Firey
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 (although not being canon), Firey used "Oh my spark" once for his OMG moment after finding that Bfdi is back.
Book
Book's OMG moment is "Oh my Word", used twice.
Fries
Fries' OMG moment is "Oh my Potatoes", used twice.
In Welcome Back, Fries's other OMG moment is "Oh my tater", used once.
Gelatin
Gelatin's OMG moment is "Oh my collagen", used once in a video including BFDIA 6 deleted scenes.
Barf Bag
Barf Bag's OMG moment is "Oh my SAP", where SAP stands for "sick airplane passengers". It was used when Lollipop declined her to be on the same team as her.
Stapy
Stapy says "Oh my GOD" in an unused/deleted line for Today's Very Special Episode. It can be found in the .fla files.
Donut
In Four Goes Too Far it was considered to have Donut say something along the lines of "Oh Dear God", but was replaced with "This can't be real" because according to Cary they didn't want to have God in a BFB episode.
Marker
Marker's OMG moment is "Oh my Artist", used once in Today's Very Special Episode. It was used when he summoned Four.