Which, if any, dragon types would you recommend for someone who wants to branch into them?
General notes:
The smallest and lightest of the dragon types, applin are native to Galar, with a small introduced population in Paldea. With two evolutionary forms to choose from, the applin line is a perfect start for people looking to get into dragon keeping.
General care:
The applin is a very small pokemon, easily mistaken for a bug type when moving between apples. It has a very delicate skin, and I don't recommend handling it without gloves, as the salts on your skin can make it uncomfortable. The apples it lives in are both food and shelter in one, and if it doesn't have access to apples it begins to dehydrate. An applin can become weak enough to die if deprived of shelter for longer than 3 days, and it is utterly unable to defend itself.
When happily ensconced in an apple, however, the applin is very easy to care for. Secretions in its skin slow down the decaying process of its home, and one large apple can last an applin just over two weeks before it's depleted and it needs a new one. Don't panic if you accidently fumble its apple, as it licks a sticky saliva over the apple its hiding in that hardens to a tough coating.
Finding an applin is fairly easy, and often if you approach apple farmers in Galar asking for applin they'll thank you for it. Applin infestations can damage their crops.
If your applin is suddenly going from an apple a fortnight to multiple apples a week, it's ready to evolve. I've already offered advice here on what to do, but now we'll go over the different care requirements of the evolved forms.
The flapple is a highly strung pokemon. It has no teeth, but with glands that spray a nasty acid when threatened, it doesn't need them. They make excellent warning systems, which is a polite way of saying they'll scream loudly at the slightest strange noise or sound. Belligerent and determined, they have the dragon attitude crammed into a body that weighs just under a kilo. Despite this, they're largely frugivorous, eating soft berries and the occasional bug pokemon. The acid in their cheek pouches can be used to dissolve harder foods, but they prefer softer ones like blukberries.
The appletun is markedly different. Slightly larger, but not by much, they tend to be nearly half a metre in height and around 13 kilograms. They're calm and sedate, but don't be fooled. Unlike the flapple, the appletun is largely insectivorous, using the sticky sap on its back to lure in bug pokemon. This makes up most of its diet, and if you live in an apartment block, you may have to provide feeder pokemon if it doesn't like kibble. Though unless you have a particularly fussy specimen this is unlikely. Most appletun enjoy the standard insectivore kibble.
Appletun also require a lot of cleaning, as that sticky nectar gets everywhere. Though easy to remove with warm water and a cloth, if you have sensory issues relating to textures, you may struggle with this pokemon.
Tiny and lightweight, with diets fairly easy to accommodate needs, the applin is that rarest of rare pokemon: an easy care dragon type.
Care rating: Green
Training:
The applin itself is surprising courageous with a trainer at its back, and is willing to throw itself into battle. As well, the entire line is pretty sharp, and picks things up well.
With the flapple, teaching it to not spew acid at the slightest noise of VITAL. Socialization training is the first thing you need to get onto when you get an applin if you intend to evolve it into flapple. They'll always be nervy, but if you can teach them to stop and check in with you instead of screaming and spraying, then they're excellent watch pokemon and battlers.
Appletun have a strong history as service pokemon for trainers with anxiety.
Training rating: Green.
Safety:
This one gets one of my rare "variable" ratings, as each evolution is different. Applin of course are solid greens, lacking any teeth, claws or venom. And the entire line is quite small and lightweight, which is one of the major safety issues with dragon types.
Appletun are slow, sedate and quiet, and though they'll spray sticky nectar if they feel threatened, this does nothing worse than burn slightly if it gets in the eyes, and can be washed off.
The flapple is as dangerous as it gets, which to be fair, is pretty dangerous. That acid is no joke, and was in fact used long ago in Galar to do metal etching. With good training, it can restrain this weapon, but I still wouldn't trust flapple near small children.
On another note. If you encounter a clay coloured flapple in the wild, that's NOT a shiny. Quietly back away. Flapple repair damage to their apple shell with a clay coloured secretion. That flapple is a high level, VERY experienced battler, and is likely very dangerous.
Safety rating: Variable
Overall ranking.
With an easy early evolution and a small compact body plan, the applin line is excellent for those looking to get into dragon keeping, whether you want something friendly and fun, like the appletun, or a steady ramping up of challenge, like the flapple. You really couldn't ask for a better starter dragon.