I play one deck solo . Historically i have always used two or three spheres cherry picking cards, but getting resources for all spheres when needed was always a bit tough. I thought one sphere (apart from spirit maybe) would never work well as there are cards you really want that are suddenly unavailable - however that may be changing.
I recently bought the Angmar Cycle and Rossiel made me finally try a Lore only deck for the first time for over 2 years, and wow it did work well, adding in the Rivendell Minstrel for a song and a splash of spirit threat control i found i had plenty of lore resources and could generate a lot of varied allies in play, and with burning brand and elf cloak Rossiel ended up defending everything that enemies threw at her. Plus you can even discard cards occasionally when in the victory display. This was a fun and magical deck and you have a lot of enemy control on hand. Actually i felt lore is quite well set up to cope even without Rossiel as you have traps and shadow protection.
I am now wondering if other spheres are also more up to the job of solo play now. I know a recent tactics hero even had some questing ability. I may have to try and move into playing more one sphere decks as this will utilise cards i have not managed to get into play before given i have tended to stick to old favourites. I quite like the idea of playing mono spheres as it does make the deck easier to build in that you are largely just looking through one sphere of cards to choose from - then perhaps consider a song and one or two cards that you really dont want to leave behind such as unexpected courage or light of valinor. I liked the process more than looking through the whole box of cards each time.
Edited by Crusaderlord