New on FamilySearch the collection England, Cornwall and Devon Parish Registers, 1538-2010 has 202,481 browse images.
Most are Cornwall parishes, you likely won't want to read through them all:
Altarnon, Antony, Baldhu, Blisland, Boconnoc, Bodmin, Bolventor, Botus Fleming, Boyton, Bradoc, Breage, Budock, Calstock, Camborne, Camelford, Cardinham, Carnmenellis, Charlestown, Colan, Constantine, Cornelly, Crantock, Creed, Crowan, Cubert, Cuby, Cury, Davidstow, Duloe, East Looe, Egloshayle, Egloskerry, Falmouth, Feock, Flushing, Forrabury, Germoe, Gerrans, Godolphin, Gorran, Grade, Gulval, Gunwalloe, Gwennap, Gwinear, Halsetown, Hayle St Elwyn, Helston, Herodsfoot, Hessenford, Illogan, Isles of Scilly, Jacobstow, Kea, Kenwyn, Kilkhampton, Ladock, Lamorran, Landewednack, Landrake with St Erney, Landulph, Laneast ,Lanhydrock, Lanivet, Lanlivery, Lanreath, Lansallos, Lanteglos by Camelford, Lanteglos by Fowey, Launcells, Launceston St Thomas, Lawhitton, Lelant, Lesnewth, Lewannick, Lezant, Linkinhorne, Liskeard, Little Petherick, Lostwithiel, Ludgvan, Luxulyan, Mabe, Maker, Manaccan, Marazion, Marhamchurch, Mawgan-in-Meneage, Mawnan, Menheniot, Merther, Mevagissey, Michaelstow, Millbrook, Minster, Morvah, Morval, Morwenstow, Mullion, Mylor, Newlyn East, Newlyn St Peter, North Hill, North Petherwin, North Tamerton, Otterham, Padstow, Par, Paul, Pelynt, Pencoys, Pendeen, Penwerris, Penzance Madron, Penzance St Mary, Penzance St Paul, Perran-ar-worthal, Perranuthnoe, Perranzabuloe, Phillack, Philleigh, Pillaton, Port Isaac, Porthleven, Poughill, Poundstock, Probus, Quethiock, Rame, Redruth, Roche, Ruan Lanihorne, Ruan Major, Ruan Minor, Sancreed, Sennen, Sheviock, Sithney, South Hill, South Petherwin, St Agnes, St Allen, St Anthony in Meneage, St Anthony in Roseland, St Austell, St Blazey, St Breock, St Buryan, St Cleer, St Clement, St Columb Major, St Columb Minor, St Day, St Dennis, St Dominick, St Endellion, St Enoder, St Erme, St Erney, St Erth, St Ervan, St Eval, St Ewe, St Gennys, St Germans, St Gerrans, St Gluvias, St Hilary, St Issey, St Ive, St Ives, St John, St Juliot, St Just in Penwith, St Just in Roseland, St Keverne, St Kew, St Keyne, St Levan, St Mabyn, St Martin by Looe, St Martin in Meneage, St Mawgan-in-Pydar, St Merryn, St Mewan, St Michael Penkevil, St Minver, St Neot, St Pinnock, St Sampson, St Stephen in Brannel, St Stephens by Launceston, St Stephens by Saltash, St Stithians, St Teath, St Tudy, St Veep, St Wenn, St Winnow, Stoke Climsland, Stratton, Talland, Temple, Tideford, Torpoint, Towednack, Tregony, Treleigh, Tremaine, Treneglos, Tresmere, Trevalga, Treverbyn, Trewen, Truro, Truro St George, Truro St Mary, Truro St Paul, Tuckingmill, Tywardreath, Veryan, Warbstow, Warleggan, Week St Mary, Wendron, Whitstone, Withiel, Zennor.
The Devonshire parishes are:
St Giles on the Heath, Werrington.
You can search 171,083 records, obviously more images are available to browse than are indexed.
Baptisms go to 1910, marriages to 1935, and burials to present.