General Concepts:
* Truth: The state of being in accordance with fact or reality.
* Time: The indefinite continued progress of existence and events in the past, present, and future regarded as a whole.
* Thought: The process of thinking, or an idea or opinion produced by thinking.
* Talent: Natural aptitude or skill.
* Trust: Firm belief in the reliability, strength, or truth of someone or something.
* Theory: A supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained.
* Temperament: A person's or animal's nature, especially as it permanently affects their behavior.
* Tension: Mental or emotional strain.
* Terror: Extreme fear.
* Tradition: The transmission of customs or beliefs from generation to generation, or the customs or beliefs themselves.
* Transformation: The act or process of changing in form or appearance.
* Transparency: The quality of being transparent.
* Tranquility: A state of peace and quiet.
* Tendency: An inclination towards a particular characteristic or type of behavior.
* Tolerance: The ability or willingness to tolerate something, in particular the existence of opinions or behavior that one does not necessarily agree with.
* Triumph: A great victory or achievement.
* Trouble: Difficulty or problems.
* Truthfulness: The quality of being truthful.
More specific abstract nouns:
* Technology: The application of scientific knowledge for practical purposes.
* Talent: Natural aptitude or skill.
* Temperance: Moderation, especially in eating and drinking.
* Tolerance: The ability or willingness to tolerate something, in particular the existence of opinions or behavior that one does not necessarily agree with.
* Treachery: Betrayal of trust.
* Transience: The state of being transient.
* Tragedy: A disastrous event, especially one that involves great loss of life, suffering, or destruction.
* Trepidation: Fear or anxiety.
* Turbulence: A state of great disturbance or unrest.
* Tyranny: Cruel or oppressive government or rule.
This is not an exhaustive list, but it provides a good starting point.
Remember that abstract nouns represent ideas, qualities, or concepts that cannot be touched or seen, unlike concrete nouns.