Any suggestions?

EDIT: The dragon is an adult red who has destroyed multiple nations and whose name should inspire terror in the hearts of the most courageous heroes. Except, I can’t seem to think of a name that inspires terror in the hearts of the most courageous heroes. Help!

What kind of dragon?  Good or evil?  Do you want a name to inspire terror or majesty?  Do you want a title as part of the name (like “...the blue death”)?

Quote from iconarising >>

What kind of dragon?  Good or evil?  Do you want a name to inspire terror or majesty?  Do you want a title as part of the name (like “...the blue death”)?

 The dragon I have in mind is an evil red dragon whose name inspires terror and yes, a title or two would be nice! 

"Ulmaug the (Color)"

"Belgaros the Cleansing Flame"

I personally like something closer to "Skyrim" naming convention, and I like hard "k" and "g" sounds for evil names since they tend to be harsher to say (Angthrask the Blue Death was a name I used for a dragon in one campaign).  Titles could be descriptive of either the creatures appearance (color, prominent features, etc), abilities (strength, power of its breath), or ideals.  A dragon might use more than one title or change their title as they age/achieve new things.

The questions in my first post might help you figure out the title.

 Edit:  I typed this before seeing your reply post

Titles for your dragon might be "The Eternal Flame"  "The Crushing Maw" "The Red Doom" "the Indomitable" "The Conquering Inferno"

The Forest Eater is a title I used for one of my big bad dragons 

Well, if you're not overly caught up on being all serious and such, call him "Fred the Scorcher"  Maybe "Reginald of the everburning flame"  I heard of a big old Black dragon who was called "Edgar the Creeping Darkness"

More themed, maybe something fantastic like "Xanthalegust Infernus Eternus"

I used Smjorkal Cindermaw for a red dragon in my camapign, althought Smjorkal is apparently Icelandic for Buttercup so maybe not terribly frightening for a name/title. If in doubt my go to options for a name are either fantasyname generator (https://www.fantasynamegenerators.com/) or takea  word in english (whatever your native language is) and then use google translate to see what that word is in other languages and cobble something odd together.

I like giving my dragons long, airy names, like Thauraeln or Aellerix. All of the dragons in my campaign world have titles after their names, so you get Thauraeln the Bold and Aellerix the Black.

Quote from Thauraeln_The_Bold >>

I like giving my dragons long, airy names, like Thauraeln or Aellerix. All of the dragons in my campaign world have titles after their names, so you get Thauraeln the Bold and Aellerix the Black.

 There's also the names of some dragonborns I use: Shorrhiashkmargid, Nyemphuuk, and Luamrandraarges. All of them have the last name Wudaar.

Adolanda. That’s what my Wife memes her Dragon spinning wheel.

I don't have any specific suggestions, but I think either something that is either very short or very long is a good idea. Adding a title is good, but if it sounds like you are just adding stuff to it, take it out. Also, before you use it, say it a few times out loud. Make sure it does not sound confusing to hear. Also, as you say it, try to emphasize the name. I'm not saying make your voice booming every time that you say the name, though that can be helpful. Instead, try to sort of bring all of the power in the room to the dragon's name. That could be saying the name in a booming voice, but whispering the name, or saying it normally except with an edge to your voice can work well. I know this is a lot of words, but this is just what I've found to be useful.

You may want to try the Noun/Adjective + Body Part formula. For example, Venomfang the Green Dragon in LMoP.

For a red dragon, here's some sample words:

Nouns/Adjectives: Fire, Flame, Scorch, Brand, Burn, Red, Crimson, Maroon

Body Parts: Fang, Tooth, Breath, Wing, Scale, Hide, Claw, Horn, Spine, Lung

With this list and formula, you can create names like "Scorchwing, " "Crimsonhide, " "Brandclaw, " "Flamebreath, " etc. I hope this helps both you and anyone else reading this comment.

You can also use a similar formula for inn or tavern names: The + Verb/Adjective + Animal, such as "The Sleeping Goat, " "The Gray Dragon, " etc.

Quote from 54MU31 >>

You may want to try the Noun/Adjective + Body Part formula. For example, Venomfang the Green Dragon in LMoP.

For a red dragon, here's some sample words:

Nouns/Adjectives: Fire, Flame, Scorch, Brand, Burn, Red, Crimson, Maroon

Body Parts: Fang, Tooth, Breath, Wing, Scale, Hide, Claw, Horn, Spine, Lung

With this list and formula, you can create names like Scorchwing, Crimsonhide, Brandclaw, Flamebreath, etc. I hope this helps both you and anyone else reading this comment.

 This is a good way to come up with dragon names.

Quote from 54MU31 >>

You may want to try the Noun/Adjective + Body Part formula. For example, Venomfang the Green Dragon in LMoP.

For a red dragon, here's some sample words:

Nouns/Adjectives: Fire, Flame, Scorch, Brand, Burn, Red, Crimson, Maroon

Body Parts: Fang, Tooth, Breath, Wing, Scale, Hide, Claw, Horn, Spine, Lung

With this list and formula, you can create names like "Scorchwing, " "Crimsonhide, " "Brandclaw, " "Flamebreath, " etc. I hope this helps both you and anyone else reading this comment.

You can also use a similar formula for inn or tavern names: The + Verb/Adjective + Animal, such as "The Sleeping Goat, " "The Gray Dragon, " etc.

 I like this convention for deciding what regular townsfolk call a dragon. They wouldn't know its real name, or they might be too superstitious to say it, or they might simply not like pronouncing something so foreign.

For my fancy "true" names, I second the utility of Google translate. I'll designate a reference language for dragons in the campaign, and then make names from translated words in that language or just cobble together some of the common sounds into something I like.

Quote from scatterbraind >>

Quote from 54MU31 >>

You may want to try the Noun/Adjective + Body Part formula. For example, Venomfang the Green Dragon in LMoP.

For a red dragon, here's some sample words:

Nouns/Adjectives: Fire, Flame, Scorch, Brand, Burn, Red, Crimson, Maroon

Body Parts: Fang, Tooth, Breath, Wing, Scale, Hide, Claw, Horn, Spine, Lung

With this list and formula, you can create names like "Scorchwing, " "Crimsonhide, " "Brandclaw, " "Flamebreath, " etc. I hope this helps both you and anyone else reading this comment.

You can also use a similar formula for inn or tavern names: The + Verb/Adjective + Animal, such as "The Sleeping Goat, " "The Gray Dragon, " etc.

 I like this convention for deciding what regular townsfolk call a dragon. They wouldn't know its real name, or they might be too superstitious to say it, or they might simply not like pronouncing something so foreign.

For my fancy "true" names, I second the utility of Google translate. I'll designate a reference language for dragons in the campaign, and then make names from translated words in that language or just cobble together some of the common sounds into something I like.

 Good point. So it really boils down to what you need. For example, the formula works for a local rumor in a tavern to act as a plot hook, while the true name is best for a monologue from the big baddie. But it's worth mentioning that the formula may work as the dragon's true name, but in common. The long, complicated true name could simply be the draconic translation.

Quote from 54MU31 >>

You may want to try the Noun/Adjective + Body Part formula. For example, Venomfang the Green Dragon in LMoP.

For a red dragon, here's some sample words:

Nouns/Adjectives: Fire, Flame, Scorch, Brand, Burn, Red, Crimson, Maroon

Body Parts: Fang, Tooth, Breath, Wing, Scale, Hide, Claw, Horn, Spine, Lung

With this list and formula, you can create names like "Scorchwing, " "Crimsonhide, " "Brandclaw, " "Flamebreath, " etc. I hope this helps both you and anyone else reading this comment.

You can also use a similar formula for inn or tavern names: The + Verb/Adjective + Animal, such as "The Sleeping Goat, " "The Gray Dragon, " etc.

 Do this, then throw it into google translate and just scroll through all the languages until you find something cool.

Overlord firebreath. Titles: the terror of all planes, the dragon of ruin, he/she who destroys forests, he/she who shall be the end of bahamut.

Quote from IamSposta >>

Adolanda. That’s what my Wife memes her Dragon spinning wheel.

On what level of (un)reality does your wife have  a spinning wheel? :) Is that a game thing, or does she actually spin yarn? I'm asking because my wife spins :)