The community is very important for kinksters. This is where we learn skills and meet people and try things in a relatively safe environment. Trying to take you away from this environment can enable someone to abuse you without you having the possibility to discuss it with others.
Social isolation in general is a typical sign of abuse, whether it's from your family, friends, or community.
Your Partner Ignores Your Safeword
This one is related to boundaries, but is definitely more obvious: when a partner ignores a safeword.
Safewords help ensure that everyone in the relationship has a say in what happens to them - yes, even submissives, slaves, or bottoms. Ignoring a safeword is a major red flag, and a sign that you should consider ending the relationship as soon as possible.
Your Partner Ignores Your General Well-being
This is a more diffuse, subtle sign of abuse, but you should still be on the lookout. If your partner asks you to do things that seem dangerous to you, or they ignore your health and well-being, it may be a sign that they are abusive.
Remember Spider Man: "With great power comes great responsibility." By giving your power away to a partner, they become responsible for these parts of your life. Even when letting go of that power is a choice, that consent doesn't free your partner from the responsibility of caring for you. Words like "I know what's best for you" in a context that's not part of your negotiated boundaries can be a sign of abuse.
Remember: the more power you give away, the more careful and "parental" a partner should be in response.
Submissives Can Also Be Abusive
If you're a top or dominant, remember that bottoms and submissives can also be abusive. They are abusive in ways that are both similar and different: isolation and boundary crossing, for example, can happen from both sides. Submissives can use emotional abuse and gaslighting as well.
Abuse can happen in any relationship. Although being kinky isn't abusive per se, kinksters can still be abusive, and can use kink to justify their behavior. That's why it is important that you understand the signs of abuse. This is especially true in kinky relationships, where the signs can harder to spot.