Crafting and trading.
What I'd love to do is go to the local tavern and throw a couple back, meet some new people, and play some darts, cards, chess, or some other simple social minigames. Basically, I'd love for cities to offer some sort of out of combat social frameworks that we haven't really experienced yet in past MMOs.
Farming materials - for some reason, I've always liked finding far off corners of the world that don't get frequented much and slowly grinding out some materials and (as a bonus, not the main attraction) experience.
Crafting - using those materials I went out and so painstakingly gathered. I love crafting in games and, hopefully, Pantheon will making crafting "worth it" again. So many games have crafted gear being either inferrior to dungeon/raid drops (even epic crafted gear with rare mats and long cooldown timers), super expensive and time consuming in terms of mats and the amount of crafts needed for skill ups - or BOTH. But even for all that, I love crafting. Especially if it is a game into itself - FF14's crafting minigame is awesome fun to me for some reason, as is its gathering minigame (which is much slimmed down compared to the crafting game).
Exploring - part of the farming, I like to go out and see the world. I tend to be a cautious explorer, but as long as there's a healing capable class that's at least decent at soloing at or somewhat below level mobs, I'll be out in the world looking around and trying not to die as I find new and exciting things to look into, materials to farm, and cool vistas to see and explore.
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Outside of that, there's always tidying up my bank or the guild bank, visiting guild housing if it's available in the game, or traveling between places/visiting towns I like.
EDIT: Oh, and almost forgot, but buffing and healing newbies is also something I love doing! Make sure I can buff people I'm not partied with and any level, okay!? :)
If I can't find a group I make one.
As for filling downtime I expand my kit, being unprepared for a situation is not my style. I need armor with saves, weapons with procs to supplement what a group lacks (snare hammer, tash stick etc), clickies and potions to supplement what I lack, WR bags, extra food for dummies who forgot theirs, peridots for slacker clerics, etc.
1) Exploration of the world and discovery of things that I can exploit as a solo player, be it a quest, or killing something or things, observing another solo player in action, or gathering items for profit.
2) If I am a much higher level toon, helping others without being too helpful or too pushy.
3) Try to find just one other person to run with and do something fun. Maybe even goofy just for laughs.
4) Working on spells and spell components, organizing bags and bank, Buying supplies.
5) Try crafting for 30 min. then go crazy and find something else to do.
6) follow a group into a dungeon and observe, and maybe get a spot if one opens up.
7) Work on my Robe collection.
1) Help low lvl guildies xp / buff them or just mentor with them (if option is available)
2) Look for someone who s also lfg and start buiding a group or duo with them
3) Going and finding the most challenging mob (i dont get resisted by) and try to solo it
4) Helping newbies kill stuff and setting up a free buff station in newbie zone
5) Hanging out in a trading zone and watching out for bargains
6) Throw up an invis spell and go exploring in dungeons and finding new safe(r) spots to camp in the badass overland areas
7) Taking epic screenshots of my character looking thoughtfully into the distance with a nice background :p
8) Crafting (if i am completely out of things to do) Yet to be fully enticed into crafting in MMO's but i am hoping Pantheon might be the game to get me interested in crafting!
If I can't find a group when logging in then I tend to do the following, depending on what's available.
The first is leveling an alt. While it's not usually my instant "go to" option, I do always love experiencing games from a different angle. Playing a new race and class in a whole new zone definitely can help with that.
Second is working on reputations. I've always been a big fan of in game reputations with factions. Getting rep up to get some cool unique reward, even something small and/or purely cosmetic is always neat. It's something that allows for small bits of progress to take place over a longer period of time.
Finally, I do love crafting. Granted it has to be a good system. Not necessarily the most complex, but has to have a good balance of reward vs. effort. I enjoy when some days I can make some pretty simple things and do some trading, either in person with players or on an auction house. The next day I might want to dig deeper and farm some harder to obtain, and possibly rarer, materials in order to make some items that are worth significantly more.
These are just some of my thoughts of what I typically enjoy doing during my MMO playtime.
I never had a problem finding or starting a group.
Would log in and get tells to join groups for 7 years in EQ, never used LFG once.
When I wouldnt have the time to group I would do things like craft, fish or just play the market.
Always thought it was odd when people would say they couldnt find a group for hours or they just needed a better LFG tool.
Well, hopefully I'll be on a PvP server, so there should rarely be any need to "find" something to do... :)
However, if there was no PvP action, there is always crafting, gathering resources, exploring, trying to find a way to solo something you shouldn't be able to, helping lowbies, etc.
Something else I'd like to do that I didn't see anyone mention is decorating (or redecorating) my house. We are getting houses, right?