The Theravada suttas are the early oral records (later written down in Pali) of the 10,000+ dharma talks Shaymanuni Buddha gave over four decades. There is no structure, and lots of repetition. When they were collected several hundred years after the Buddha’s death, they were collected by length rather than by topic. There is a guide to the suttas at the Access to Insight website

The Heart of Buddhist Meditation by Nyanaponika Thera is the still-classic anthology of sutta excerpts relating directly to meditation practice.

Collections of the major Theravada suttas have been published by Wisdom Publications in several volumes:

• The Middle Length Discourses of the Buddha: A Translation of the Majjhima Nikaya by Bhikkhu Nanamoli
• The Connected Discourses of the Buddha: A Translation of the Samyutta Nikaya by Bikkhu Bodhi
• The Long Discourses of the Buddha: A Translation of the Digha Nikaya by Maurice Walshe

A helpful anthology of sutta excerpts, arranged by topic, has been published as In the Buddha's Words: An Anthology of Discourses from the Pali Canon by Bhikkhu Bodhi.

Another good anthology is the four-volume Handful of Leaves, translated by Thanissaro Bhikkhu; see the Sati Center website.

Two suttas that focus on practice are the Anapanasati (Mindfulness of Breathing) and the Satipatthana (Four Foundations of Mindfulness).

The Anapanasati Sutta translations and commentaries include one by Thanissaro Bhikkhu, Buddhadasa’s Mindfulness with Breathing for Serious Beginners, Larry Rosenberg’s book Breath by Breath, and Thich Nhat Hanh’s book Breathe! You Are Alive.

Satipatthana Sutta translations and commentaries include the Thanissaro’s, Soma Thera’s The Way of Mindfulness, Thich Nhat Hanh’s book Transformation and Healing, and Goenka’s Satipatthana Sutta Discourses.

There are several compilations of excerpts from the Mahayana sutras, such as The Buddhist Tradition: In India, China and Japan (edited by William Theodore De Bary) but because of the number, length, and diversity of the Mahayana sutras, the published collections of excerpts barely scratch the surface.

A few of the major Mahayana sutras are listed below.

Prajnaparamita Sutras (Perfection of Wisdom) (Heart Sutra, Diamond Sutra, & longer 8000, 25000, and 100000 line versions)
~ Red Pine’s translations of and commentaries on the Heart and Diamond Sutras are invaluable.
~ Edward Conze translated the Heart and Diamond Sutras and the 8,000- and 25,000-line versions
~ DaeJang Gyong Research Institute translation edited by Richard St. Clair available online.

The Flower Wreath Sutra has been translated by Thomas Cleary. There is a multi-volume commentary by the 20th century Chinese master Hsuan Hua.

The Lankavatara Sutra translated by D.T. Suzuki available online.

The Lotus Sutra translated by Burton Watson available online.

The Vimalakirti Sutra translations by Burton Watson and Robert Thurman have been published.

The Pure Land Sutras Shin Dharma New translation and Jodo Shu Research Institute translation

The Mahaparinirvana Sutra (different from the Pali Mahaparinirvana Sutta). The Kosho Yamamoto translation as revised by Dr. Tony Page is available online.

The Shurangama Sutra several translations available online.

Tathagatagarbha Sutra translation by William H. Grosnick available online.

In addition to the links above, there are many online translations available through M.T. Lee’s website Mahayana Buddhist Sutras in English.