Island Heat, Pink Lotus & Tropic Sunrise make beautiful sunset type nails if you use them in blended stripes over Studio White/Cream Puff. Fabulous under stamping. I've also used these, along with Midnight Tide, in random patches under the Moyou Kaleidoscope stamping plates, it looks really effective. Island Heat is also really popular with my clients as full coverage over Electric Orange. These bright additives also make very bright, almost neon, nails when mixed with acrylic powder for enhancements.
I love Pink Gold Sparkle! It adds extra depth & sparkle to any CND Shellac pink and looks beautiful over Lilac Longing, but it also looks gorgeous as a fade over Black Pool or even better over Midnight Swim.
I'm not a great fan of Locket Love, it's not a shade that my clients tend to choose, but I sometimes use it as an accent nail with one of the Lecente gold glitters or with stamping over the top. It's also quite nice to use under a darker colour and etch out shapes into the darker layer before curing so that the Locket Love shows through in the detail. It does tend to come out more at Christmas time.
I don't have Titanium Pearl so I can't help you much with that, sorry.
Try having a play about on some colour pops. Bear in mind that how the additives look when you first put them on is not necessarily how they will look after you've top coated them! I've also learned that some combinations that I'm really not sure about are very popular with my clients. Hope that helps.