There are variations in soil acidity and this is by no means a complete list of acid loving plants, but I hope it is helpful:
pH 4.5 to 5.5
Achmines
Adiantum
African violet
Aloe
Amarylis
Aphelandra
Aurucaria - Norfolk Pine
Azalea
Begonia
Caladium
Calathea
Crossandra
Cyclamen
Dieffenbachia
Epiphyllum
Gardenia
Hydrangea
Impatiens
Maranta
Pellaea - a fern
Peperomia
Pilea
Polypodium
Primula
Rechsteineria
Saxifraga
Scindapsus
Streptocarpus
Syngonium
Zygocactus
Woody Ornamentals and their pH preferances
pH 4.0 to 5.0
Spruce, Black
pH 4.5 to 5
Azalea
pH 4.5 to 6
Birch, European (White)
Heather
Rhododendron
pH 5 to 6
Most coniferous species would prefer a soil of this pH
Fir, Balsam
Hemlock
Pine, Jack less tolerant of pH above 6
Pine, Loblolly
Pine, Red Pinus resinosus less tolerant of pH above 6
Spruce, White
pH 5.0 to 6.5
Beech
Oak, Pin
Tamarack
pH 6 to 7
Most Hardwoods prefer a soil of this pH
Fir, Douglas
Oak, Black
Pine, White
Spruce, White
Yew, Japanese
pH 6 to 7.5
Ash, White
Maple, Sugar
Spruce, Colorado
Sycamore
pH 6 to 8.0
Walnut, Black
Vegetable crops and their pH preferances
pH 4.5 to 5.5
Radish
Sweet Potato
pH 4.8 to 5.5
Potato
pH 5.5 to 6.5
Endive
Parsley
Pepper
Rhubarb
Soybean