Although there is no perfect curriculum, there are materials that can be helpful and that need less modifications for kids with learning challenges. The following list contains the books and series from various publishers that I most often recommend and that many families have used successfully over the years.
Educators Publishing Service (Explode the Code, Recipe for Reading, Attack Math, Spellwell, Reading Comprehension in Varied Subject Matter, The Paragraph Book series, Writing Skills, It’s Elementary, Starting Comprehension, How to Teach Spelling)
Pro-Ed (Reading Milestones - a sight reading program for children with severe language disorders; Time Concept Series; The Time is Now series; I Can Write; Counting Money; Teaching Competence in Written Language; Metacognitive Program for Treating Auditory Processing Disorders)
Critical Thinking Press (Mind Benders, Building Thinking Skills, Visual Perceptual Skill Building)
Future Horizons (No More Meltdowns, Aspergers - What Does It Mean to Me?, Navigating the Social World)
Rainbow Resource (Pathway Readers: simple, wholesome readers that allow a mix of phonetic and sight word practice for 1st - 6th grade reading levels; MCP Math books are also available from Rainbow resource. these are very basic math books by grade level that offer fairly clean pages and a lot of practice for 1st - 6th grade levels; Key to Math: these math worktexts are great for pre-algebra, basic algebra and basic geometry. They come in small "bite sized" workbooks which can be written in and are not overly cluttered.)
Visual Tracking materials are available form Academic Therapy Publications:
Wieser Educational Offers a large variety of materials for struggling learners including the Pacemaker and AGS textbooks. These are High School materials that are written at a 4th-5th grade reading level. Ideal for students with good comprehension but who struggle with reading.
K5 Learning - great no frills, inexpensive downloadable workbooks at levels K - 5th grade. Very clean and don't look too babyish.