This list is not complete but covers places to go to see a generally good range of wildflowers, insects and birds. Those in North Wales & Anglesey are highlighted in red.

wildflowers and other plants 

Kenfig National Nature Reserve (South Wales)
Newborough Warren National Nature Reserve 
Anglesey Fens National Nature Reserves 
Cwm Idwal National Nature Reserve
Meirionydd Oaks National Nature Reserve
Cae Blaen Dyffryn
Llyn Eiddwen National Nature Reserve – aquatic plants
Coed Rheidol
Craig Cerrig Gleisiad a Fan Frynych
Merthyr Mawr National Nature Reserve (South Wales)
Morfa Dyffryn National Nature Reserve
Morfa Harlech National Nature Reserve 
Cwm Cadlan National Nature Reserve
Ynys Enlli/Bardsey Island
Bryn Pydew North Wales Wildlife Trust Reserve 
Allt Rhyd y Groes National Nature Reserve – Mosses and Lichens
Cors y Llyn National Nature Reserve
Craig y Cilau National Nature Reserve
Allt y Benglog National Nature Reserve – Mosses and Lichens
Gregynog National Nature Reserve – Lichens and Trees

Anglesey Fens National Nature Reserves
Kenfig National Nature Reserve
Newborough Warren National Nature Reserve
Cae Blaen Dyffryn Plantlife Reserve
Dyfi National Nature Reserve
Morfa Dyffryn National Nature Reserve
Bryn Pydew North Wales Wildlife Trust Reserve

insects

Aberbargoed Grasslands NNR
Cors Fochno – Dyfi National Nature Reserve
Meirionydd Oakwoods National Nature Reserves
Pengelli Forest National Nature Reserve
Merthyr Mawr National Nature Reserve
Morfa Dyffryn National Nature Reserve                                                                       Mynydd Marian, Llysfaen Local Nature Reserve
Rhos Llawr Cwrt National Nature Reserve
Bryn Pydew North Wales Wildlife Trust Reserve
Cors y Llyn National Nature Reserve
Gregynog National Nature Reserve

birds

Skomer National Nature Reserve (West Wales)
Newport Wetlands National Nature Reserve (South Wales)
South Stack Nature RSPB Reserve 
Cors Caron National Nature Reserve
Crymlyn Bog and Pant y Sais
Valley Wetlands RSPB Reserve
Cors Dyfi Montgomeryshire Wildlife Trust Reserve
Ynys-hir RSPB Reserve
Lake Vyrnwy RSPB Reserve (Northwest)
Grassholm National Nature Reserve (West Wales)
Ramsey National Nature Reserve (West Wales)
Y Berwyn National Nature Reserve
Gower Coast National Nature Reserve (Southwest)
Ynys Enlli/Bardsey Island National Nature Reserve
Rhinog National Nature Reserve
Spinnies Aberogwen North Wales Wildlife Trust Reserve
Allt Rhyd y Groes National Nature Reserve
Wildfowl and Wetlands Centre
Arthog Bog RSPB Reserve
Gwenffrwd Dinas RSPB Reserve