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.
Several characters may use the regular "Oh my God/gosh" instead of a thematic variant. These characters include Tennis Ball, Stapy, Bubble (though pronounced "goish"), Bomby, Pencil, Eraser, Yellow Face, Nickel, Gelatin, and Pen.
Some characters have 'WTH' (what the heck) moments, like Snowball (What The Flake) and Match (What The Woodsicle).
Barf Bag's OMG moment is "Oh my SAP", where SAP stands for "sick airplane passengers". It was used in "Getting Teardrop to Talk", when Lollipop declined to be on the same team as her and in "Don't Dig Straight Down", when Bomby insisted on igniting himself so his team could be blown to the surface. She has also said "Oh gag" at 18:26 of "Don't Dig Straight Down".
Book's OMG moment is "Oh my Word", which was used twice.
Bubble's OMG moment is "Oh my Bubble Blower!", sometimes shortened to "OMBB!"
In Season 1 Coiny's OMG moment was "Oh my Midge" or OMM.
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.
In "Don't Dig Straight Down", Donut says "Oh my bakery" in response to Barf Bag regaining consciousness after being filled with water.
Firey's OMG moment is "Oh my Oxygen!", used once after getting barfed on.
In BFDI Is Back, when he discovers the release date for IDFB 1, he says, ”Oh my Spark!”
In other episodes, Firey says "Oh my gosh".
FlowerIn Insectophobe's Nightmare 2, Flower states her OMG as "Oh my Gardener!"
In Return of the Rocket Ship, though not a true "OMG" moment, Flower says "Holy Aphid".
Fries' OMG moment is "Oh my Potatoes", used twice.
In Welcome Back, Fries's other OMG moment is "Oh my tater", used once.
Also, in "Barriers and Pitfalls" Leafy said "OMZ", although no one knows what it stands for.
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 phrase (OMQ, OMW, OMZ) more than 10 or even 20 times.
Snowball's OMG moment was said at the biggest and final rejoining ceremony of Season 1 as "Oh my Snowflake!"