Macro's that are actually useful ?

[Heartlly]

Warrior Macro to swap Inner Beast and Steel Cyclon with Fell Cleave and Decimate when useing the appropriate stance

/micon "Defiance"
/ac "Defiance" <me>
/crosshotbar set "Inner Beast" 2 RAU
/crosshotbar set "Steel Cyclone" 2 RDL

/micon "Deliverance"
/ac "Deliverance" <me>
/crosshotbar set "Fell Cleave" 2 RAU
/crosshotbar set "Decimate" 2 RDL

The 3 letters work like so:

First letter (either Left or Right) dictates whether it's the left or right crosshotbar (aka you hold L2 or R2)
Second letter (either Direction or Aaction) dictates whether it will then be on the d-pad or face (action) buttons
Third letter (Up, Right, Down or Left) dictates which button the skill will then go on, either the obvious directional button or the appropriate face button (Triangle being up, Circle being right, etc).

[Paladinleeds]

Macro snip

Similarly, if you're on PC, you could use mine.

/macroicon Defiance
/ac Defiance
/e I will show you TRUE Defiance!
/hotbar action "Inner Beast" 1 10
/hotbar action "Steel Cyclone" 1 11
/hotbar action "Defiance" 4 3

/macroicon Deliverance
/ac Deliverance
/e I bring unto thee Deliverance!
/hotbar action "Fell Cleave" 1 10
/hotbar action "Decimate" 1 11
/hotbar action "Deliverance" 4 3

For hotbar action, it goes ability name, hotbar number (you get 10 hotbars), position on hotbar (1 is furthest left, 12 is furthest right).

Also, /e stands for /echo, which means only YOU see it, but it can have sound effects that play too. Like my swiftress macro for example.

/macroicon swiftcast
/ac "swiftcast" <me>
/wait 1
/p You cannot escape that easily <t>! Time to Raise yourself from the grave and Ascend into Heavensward! Resurrection incoming! <se.7>
/ac resurrection <t>
/ac raise <t>
/ac ascend <t>
/wait 59
/echo Swiftcast off cooldown - Emergency Ress available <se.1>

[Rawrz]

In my experience it's better to hotbar change than to hotbar copy for hardware lag reasons.

[Slappah]

I live for countdown macros. We get to a boss in a dungeon and the tank stops moving in front of the boss to make sure we're all there. Waits 15 seconds... hit's Z to pull out their weapon. "This must be it!" I think to myself as I hit QS HE B4B and RS... but the tank does nothing... My cooldowns are gone :^).

People actually keep Z bound to draw weapon?

It's such a good key to have bound for other stuff D:

[Canadane]

All abilities tied to it are oGCD if they involve abilities (with the exception of the provoke macro which also fires Shield Lob/Tomahawk/Unmend a second later if I fail to react after the provoke, but I am getting better at manually handling the bit after the provoke). I use a provoke macro, a SwiftRess macro (no hard ress one), one for my Hallowed Ground (Holmgang and Living Dead are NOT macro'd), and a pull macro. I also make macros to announce certain mechanics and how to deal with them, or manage positionals, etc. They're the ones that announce stuff to players that I actively use.

I also have 2 macros that don't announce stuff. These are Defiance and Deliverance. What these do is they /echo what ability got used, and adjust my hotbars so that abilities I can't use get hidden for abilities I can use. When I use the Defiance macro it adds Inner Beast and Steel Tempest to my hotbars, and vice-versa for Deliverance, which adds Fell Cleave and Decimate to my hotbars. When they're used, they replace the abilities found in the other.

These are all abilities you want to be able to go off no matter what.
So macroing them is the worst way to achieve this. All macros cannot be queued like an ability can.

[Rawrz]

Travel macro (with mount)

/ac sprint <t>
/mount "Company Chocobo" [Place your main mount here]
/mount "Secondary Mount" [if the company Chocobo is not your main mount place it here. If it is your main mount put your runner up, for when your choco is stabled]
/ac Sprint
/macroicon sprint

What this does is:
It lets you Sprint towards something without attempting to mount if you target anything, even yourself.
It will have you mount if Sprint is on CD or if you're not targeting anything.
It will summon your chocobo companion as a mount instead of your default, so you don't get an error while he is summoned for combat.
It will also summon your backup mount when your chocobo is stabled, if he is your default mount.
Finally, Sprint is repeated at the end so that if you are In a place where your mount is forbidden and you aren't targeting anything, it will have you Sprint.

Figuring this out has made my hotbar much more enjoyable.

[AlphaFox]

For my healers I use a variation of these so I never have to turn away from my tank but also not affect me when doing Solo.

/micon "Stone II"
/ac "Stone II"
/ac "Stone II" <tt>

[Paladinleeds]

These are all abilities you want to be able to go off no matter what.
So macroing them is the worst way to achieve this. All macros cannot be queued like an ability can.

Honestly, with my mouse and keyboard/gamepad... they fail to go off so infrequently (maybe due to the practice I've had), that it REALLY doesn't matter to me. On the rare (and I mean extremely rare) occasion that it fails, it's fine, I deal with it. Because of how I use them reactionarily and know when it's safe to weave them in between other stuff, they pretty much always go off. Maybe I've gotten used to it, but it really isn't as bad as you make it out to be in my experience. Even when I was first using them, the failure rate was still less than 1%.

[Kitano123]

Pull macro's
Hotbar/ability swapping for war/sch pet
Raise macro's
Low mana macro
swapping abilitys like stone II/III for low level dutys when casting protect

[Dzian]

In the arr days I had a few usefull ones

My brd had /ac "blunt arrow" <f>, meant I could silence a boss even if I was dealing with adds or something. though these days next to nothing needs to be silenced so it's been relegated to just another dps skill. most frequent use was in wod so I could silence quakega even if dpsing the void portals. couple of the coils it was quite usefull aswell.

blm I had /ac "aetherial manipulation" <8> and <4> made a very usefull gtfo of the way button could "usually" really on the healers to be somewhere safe saved my ass numerous times.

couple of ones I find most usefull in general are /target <f> , attack1 and square. especially on the ps4. where as a healer in wod / voidark for example I mark the main tank as square if hes in another alliance, just a quicker way of getting him, one more regen is never a bad thing.