The Sunni Muslim world, as I see it, is divided up into the following social categories. Below are the major trends that run through this segment of the Umma.
Madhhabi Sunnis: Anyone belonging to the traditional Hanafi, Shafi`i, Maliki, and Hanbali schools, including both conservative and nominal Muslims. Madhhabi Sunnis usually express their religion through devoted worship, spirituality, and traditional law-abidance. Many sub-movements fit in this category, including most Sufis, the mystical Barelvi movement, the Deobandi movement, and those who are simply culturally Muslim. Madhhabi Sunnis are usually suspicious of Salafi, Shia, and modernist ideas and traditions, but still advocate for Muslim unity; agreeing to disagree with competing trends. Some nominal Madhhabis are influenced by Salafi revivalism and conservatism. Sufis in particular are often politically quietist and pacifistic, and have a balanced but positive view of classical Islamic civilizations.
Popular examples: Hamza Yusuf, Yahya Rhodus, Timothy Winters, Zaid Shakir, Umar Abd-Allah, Shabir Ally, Usama Canon, Suhaib Webb, Faraz Rabbani, Amjad Tarsin.
Salafis: Those who try to pursue a literal interpretation of Sunni Islam based on its most established primary hadith sources. Salafis are suspicious of secondary sources, philosophy, mysticism, traditional Sunni schools, saint-reverence, forms of religious expressions that are not explicitly supported by "sahih" Sunni hadiths, and other sects and religions. Salafis usually express their religion through theological discourse, worship, strict adherence to early practices (including having a "Muslim appearance"), and clamping down on "innovations" in Islamic practice (i.e. anything in a hadith they consider "weak", or not found in their most literal interpretations). Salafis have three noticeable sub-movements: (1) the Wahabis, who follow the Najdi Saudi theologians; (2) apolitical non-Wahabi Salafis, who follow non-Najdi figures, are focused mostly on theology and law, and are critical of Saudi Arabia's royal family and state-sponsored scholars, and (3) Militant Salafis, who seek to revive the Caliphate, establish puritan Islamic states, resist Western imperialism, and punish deviant and nominal Muslims. Salafis are very critical of Sufis and Shias, and often push for the destruction of their relics.
Popular examples: Bilal Philips, Abu Khadeejah, Yasir Qadhi, Abdur Raheem Green, Zakir Naik, Feiz Mohammed, Abu Musab Wajdi Akkari, Abu Isa Niamatullah.
Liberal Reformists: This includes Quranists and other reformists, who have a modernist humanist worldview, and see many Islamic laws and practices as outdated or obsolete. Liberal Reformists are focused on social justice and ethical principles inspired by the Quran. They are skeptical of hadith literature, Islamic scholarship, mysticism, sectarianism, and some jurisprudence. Liberal Reformists are especially critical of traditional penalties (hudud), extremism, radicalization, and laws related to gender and sexuality. The Quran is viewed as a flexible, progressive document that mostly lacks the rigidity of Islamic laws.
Popular examples: Mona Eltahawy, Irshad Manji, Maajid Nawaz, Tarek Fatah, Amina Wadud, Asra Nomani, Michael Muhammad Knight, Khalid Abou El Fadl
Muslim Brotherhood Types: They are often unaffiliated with the actual MB, but hold the same pragmatist and anti-imperialist sentiments. They are a middle-upper class educated movement that focuses on social conservatism, harmonizing modernism and traditionalism, international politics, and social justice. The MB types believe in family values, scientific/technological progress and development, and quasi-Marxist-Leninist domestic and international policies (big welfare governments and anti-Western imperialism). They are critical of Salafi puritanism, Sufi mysticism, and Shia Iran's encroachment of the Arab world. The MB types often admire the Turkish, Tunisian, and Malaysian Islamic models, which are pluralistic yet respect Islamic tradition. They are often nostalgic of Islamic civilization's golden age.
Popular examples: Tariq Ramadan, Jamal Badawi, Dalia Mogahed, Anas al-Tikriti, Jonathan Brown
Most Sunni Muslims are not very conscious of these divisions. They usually don't identify themselves with one of these labels, and all 4 trends coexist in most Sunni nations and communities. The trends also have some overlaps, and there are people that are a blend of multiple trends. Sunni scholars are more aware of the red lines due to their epistemological significance. But many Sunnis are subject to the influence of Gulf petrodollars, and therefore will take on some Salafi cliches without noticing it (or just seeing it as becoming "more religious"). I call this "Casual Salafism" - speakers like Nouman Ali Khan, Yusuf Estes, Ismail Menk, or Omar Suleiman, who are more laid-back and popular with the youth, but still have a Salafi epistemology and Salafi influences in their material.
Being conscious of these trends will allow us to better understand whom we can work with and whom we should best avoid.