A general support buff
As someone who likes playing support, mainly mage-supports (high utility mages), I do not want to play support literally 100% of the time and because of this less and less people queue up for support which means you either get super long queue times or insta queue pops when you have support or fill in either slot (especially true for support in either slot).
I don't think giving players guaranteed rewards for queuing as support is the answer (probably will introduce a bad crowd to the role). I think making support feel more like a "real role" will make players, especially solo queuers, feel more in control by adding things that can give duo-lane supports more gold to get real items so tank supports can feel like a slightly weaker top laner than a gimped one and mage supports can feel more like weaker a mid lane mage than just a CC bot.
Bandit: (The gold mastery in the utility tree) Gain 10% gold from nearby dying enemy minions that you did not execute (from +1 gold; this is pretty much +2 gold and 4-5 gold for large minions). Basic attacks against enemy champions still grant gold.
All tier 1 gold items: Another passive added on: Gain 20% gold from nearby minions and monsters that an ally champion executes.
Monsters for roaming supports can buddy up with their jungler and not feel restricted to being in lane constantly.
All tier 2 gold items: Passive upgrades to: Gain 30% gold from nearby minions and monsters that an ally champion executes.
Gold items are unchanged otherwise so this is a buff to give supports slightly more gold than they get now. "Nami... is that a Deathcap you got there?"
Remember the numbers are examples of my ideas and not a finalization.