General terms related to love/friendship:
* Philia: (Already mentioned, the base word)
* Philautia: Self-love
* Philamathia: Love of learning
* Philology: The study of language
* Philomath: A lover of learning
* Philanthropy: Love of humanity; charitable acts
* Philogynist: A lover of women
* Philanderer: A man who has casual sexual relationships with many women
* Philoprogenitive: Having a love for children
* Philoptochos: A lover of the poor
Specific types of love:
* Agapē: Selfless love, the love of God, or a spiritual love
* Eros: Romantic love, passionate love
* Storge: Familial love, natural affection, parental love
Other words:
* Philadelphia: A city named for its brotherly love
* Philharmonic: A symphony orchestra
* Philodendron: A type of houseplant
Keep in mind that while "philia" is a common root, many of these words have evolved their own meanings and nuances over time.