There are things that I find kind of exploitable. It's obviously up to community and mr. Kennedy to decide whether they are and whether they should be changed. I'd love to know what others think of them.

1. Overly easy and painless way to remove fascination/dread/restlessness.
As everyone knows, to promote an acquaintance to believer you only need a little lore of proper aspect. However, the trappings slot still accepts, and consumes, any influences, including dread, fascination and restlessness. This is by far the most reliable, fast and cheap way to remove any of those, and it's available almost immediately.
It is limited to the maximum number of acquaintances but that's way more than enough, and then there are rites. Those can be used the same way but they actually have non-trivial requirements.

2. Getting a job without starting the time.
As a physician, you have a single point of reason and a work verb initially. Which means you can get position at Glover & Glover instantly and earn infinite amount of funds without any risk or effort at all before the main part of the game even starts. Your funds won't be devoured by time, and potentially deadly timers like sickness won't spawn until the time starts.

another easy way to get rid of restlessness is painting. just use it as inspiration and it will be consumed. (doesn't work for fascination and dread though)

are you about to do something you really don't want to fail?
exit to the main menu. you now have a 'quick save'.
do you get a bad result? use the windows task manager to kill the game and when you start the game again you get to reload your 'quick save'

Well, painting to get rid of restlessness makes a lot of sense, and it requires you to use it before it turns to Dread, so I wouldn't really consider that an exploit, just a good strategy.

I'd use painting a lot more (to consume restlessness; to generate contentment), but it is time-consuming. It gets you fired from your day job.

Upgrade your passion to unlock more slots for the painting job, then use notoriety to fill those (it's worth double of what you get from mystique). I regularly pulled in 5 or 6 funds per painting from this, but of course it's risky as hell since it "preserves" the notoriety beyond its usual expiry timer.
Still, being an artist can pay big time, and with the right ingredients, you can also paint usable occult tools for all lore types. Slaving behind a desk seems mundane and boring by comparison.

Now excuse me, I need to blow some funds on more opium tincture, I feel some dread coming on... ;)

I haven't tried it, so can you tell me if pigments are consumed when you use them for painting?

They are. (Short version.)

A bit more elaborate and spoilery:

Basically, you need to put in 4 passion into the job slots, paint something worth at least 5 influence of the related lore type (you can use lore as inspiration, a suitable disciple, or, if you're feeling pick(man)y, a summoned creature of the proper lore type).

The pigment, usually a level 4 influence, will be consumed, but the picture you get is a reusable level 8 influence of the corresponding type. It's unique, though, any further attempts with the same pigment type will only produce "regular" art.

Use of summoned creatures as assistants (as opposed to sacrifices) in rites. Try the following: Rite of the Rebel Striving, knock lore, Raw Prophet (leave the last two slots empty). Congratulations, you now have a Raw Prophet breeding farm! (Try not to think about the mechanics or implications of this phrase.)

Exactly the same for Hint, Percussigant and Maid-in-the-Mirror... and Teresa, which leads to me to another loophole: Unique cards disappear only if they are at the same time on the table. If they are in use, you can have as many as you'd like. I have only been able to test it with the three unique summons, and right now I cannot think of any other use for that loophole.

Edit: Now that I think about it, I did not use Teresa (or the other two) to summon herself. Only did it again while she was on an expedition and then put her on 'Talk'. Wonder if they disappear when being together in the 'results' window. Going to bed now, I'll test that tomorrow.

I know it works for other summons, that's why I said "use of summoned creatures" instead of "use of Raw Prophets". I can also confirm the in-use thing for unique books. I had an expedition that dug up both the translated and untranslated versions of one of the books. I absent-mindedly set the untranslated version to translate and only realized the problem after translation finished. Fortunately, I had my explore verb temporarily free, so I set the first copy to be auctioned before removing the second copy from study.

They don't. I sent 2 Kings Crucible on expedition and one disappeared only when I collected cards from expedition results. They were perfectly okay together in "results" window.

Thanks for that. Couldn't get around to doing it today.

Cool }:-)

While I've never experienced this exact situation, I have seen the same "unique" book appear multiple times during a single play-through.

Shouldn't "unique" actually mean "there is only one of these in the game-world ever"? As opposed to "there may be multiples of these, but you can only have one at a time", which feels wrong somehow - either there's only one copy of this book, or there are multiple, and if there are multiple, why the need to have the "unique" mechanic - why not just allow multiple copies to exist without restriction?

It makes more sense for the unique summons since they're time-limited, so you would just be re-summoning the same entity multiple times.

It seems that game makes a lot of exceptions for cards that aren't on the table. Timers don't go for them, they don't disappear, they can't get attracted by "magnets". I suppose it's some sort of failsafe mechanism against cards suddenly disappearing in the middle of a process.
As for the uniqueness mechanic, it is at very least meaningful in case of languages, dream-world ways and rites, as multiple copies of those make no sense but they can still be acquired in a non-random way from certain sources. And it'd be confusing if you didn't get a second copy at all (as it's important to let you know that it's possible to acquire said card from this source).