I don’t like pure black or white bikes - I much prefer bold colors.
I’m “browsing” new bikes 
and would love to know in this world of dull pastels which manufacturers have colourful paint jobs (the Willier Rave in green or purple has caught me eye). Road or gravel.
Unless you go custom, you’re all outta luck on this front! Cookie-cutter bikes and ‘exciting paint jobs’ do not go hand-in-hand.
The Italian brands usually have some fun colours going on.
I really like the Cinelli colours at the moment, some nice bright 90s-style stuff. But I would say that because I have one…
Or Merida do sparkly brown in a couple of models?
Those are some 
paint jobs!
If my failing memory is correct, we’ve not had amazing, eye searingly good paintjobs since the days of Klein Attitudes… Colnagos imo don’t give cos they were pretty exclusive when they were current…
I love my Seka Exaero GR’s paintjob… from what I can tell, all of their paint is gorgeous.
The Officinal Battaglin bikes in their cromovelato finishes are about as sexy as they get. They come with a hefty price tag though…
Plenty of amazing finish options…for custom bikes. Or you can purchase an “off the shelf” bike and have it painted any way you like. The bikes pictured here are in my personal collection. The Ellis has “color shifting” paint and pictures never quite do it justice. Depending on the light and angle you are viewing it, the bike appears blue with flashes of purple and pink. The Slim Chance is a disc-brake/modern version of the old Slim Chance from the 90’s. I asked Chris Chance to construct it with all-stainless steel tubing, which he did. He tells me it’s the only all-stainless Slim in existence. It also is a coupled-frame for travel purposes. Split seat tube for the top coupler and stainless steel paragon z-coupler for the downtube coupler. The Onguza was painted in-house by “Dan from Nam’s” crew in Namibia where the bike was made.
Sadly, Carl Strong’s Pursuit Cycles is now defunct, but they made some super nice carbon frames. The paint on my Pursuit all-road bike was done by Ollie at Dark Matter in Colorado. The Alliance (AKA Erik Rolf, based in Idaho) was done by his local painter but most of the bike is unpainted Columbus XCR stainless..so sometimes no paint or minimal paint is best option. My English is another stainless frame (KVA tubing). For the paint I was inspired by British author Douglas Adams, who wrote Hitchiker’s Guide to the Galaxy. It’s like a deep purple base with airbrushed stars and galaxies meant to look like outer space…plus some words and symbols taken from the book. My Bilenky was painted with DuPont Imron automotive paint, I assume wet paint is fairly common in custom work as opposed to powder coating. The fork is a THM Scapula road fork painted to match, with hand-painted pin-stripes.
Awesome 
. How do you know what colours will work together. I’d be worried I’d get it wrong!
The Chinese companies seem to do soooo much better paint jobs. After posting this I came across Elves Bikes and they have some great colours!
It depends. You might go with variations on already-established paint plans. Or you might be working with a specialist painter that focuses mostly on bikes…and they can help you pick color combos that work best based on the overall design, or look you are going for. If they are really professionals, they won’t let you pick anything that looks horrible.
I used to have three relatively local guys who would paint my frames. Now I have none.
IMO, painting a bike is not easy as the tubes are always turning away from you. My experience with guys who paint cars was miserable, they are used to broad, flat surfaces.
Regardless of what scheme you settle on, take your time and look for someone who has painted bikes before.
Fairlight has a Plum and Irridescent Root Beer that look great. Fit, Function, Form - Fairlight Cycles
A Revel Rover option:
Obed offers a wide selection of fun colors: OBED COLORS – OBED Bikes
On the other hand, Scott offers three different shades of grey in their Addict line. Such choices! 
Orbea also offers full custom paint!
Allied is doing some beautiful paint finishes on their bikes here in Northwest Arkansas…
https://alliedcycleworks.com/blogs/stories/your-bike-is-your-canvas
You clearly want a Dario Pegoretti.
If only. Those are awesome
Handsling bikes in the UK do some excellent paint jobs
